a j\ 



■531 



THE CHEMISTRY 



OF 



COOKING AND CLEANING 



RICHARDS and ELLIOTT 




Class 



QLlAl 



Book tRs J 



THE CHEMISTRY OF 
COOKING AND CLEANING 

A MANUAL FOR HOUSEKEEPERS 



ELLEN H. RICHARDS 
S. MARIA ELLIOTT 



THIRD EDITION 
REVISED AND ENLARGED 




WHITCOMB AND BARROWS 
BOSTON 1907 



HILARY of CONGRESS 
Two Copies Received 

SEP 30 190f 

Copyrifht Entiy 

COPY B 



'No. 



A 



First Edition 

Copyright, 1881 

By Estes & Lauriat 



Second Edition 

Copyright, 1897 

By Home Science Publishing Co. 



Third Edition 
Copyright, 1907 
By Ellen H. Richards 



Alfred Mudge & Son, Inc., Printers, 
Boston, Mass., U. S. A. 



PREFACE. 



IN this age of applied science, every opportunity 
of benefiting the household should be seized 
upon. 

The family is the heart of the country's life, and 
every philanthropist or social scientist must begin 
at that point. Whatever, then, will enlighten the 
mind, and lighten the burden of care, of every 
housekeeper will be a boon. 

At the present time, when the electric light and 
the gas stove are familiar topics, there is, after all, 
no branch of science which might be of more 
benefit to the community, if it were properly un- 
derstood, than Chemistry — the Chemistry of Com- 
mon Life. 

There is a space yet unoccupied for an elemen- 
tary work which shall give to non-scientific read- 
ers some practical information as to the chemical 
composition of articles of daily use, and as to their 
action in the various operations in which they are 
employed. 

The public are the more ready for the applica- 
tion of this knowledge since Chemistry is taught 
in nearly all High Schools, and most persons have 
a dim idea of what some part of it means. To 
gather up these indistinct notions into a definite 
and practical form is the aim of this little book. 



iv PREFACE. 

There is, lingering in the air, a great awe of 
chemistry and chemical terms, an inheritance 
from the age of alchemy. Every chemist can re- 
call instances by the score in which manufacturers 
have asked for recipes for making some substitute 
for a well-known article, and have expected the 
most absurd results to follow the simple mixing 
of two substances. Chemicals are supposed by 
the multitude to be all-powerful, and great ad- 
vantage is taken of this credulity by unscrupulous 
manufacturers. 

The number of patent compounds thrown upon 
the market under fanciful and taking names is a 
witness to the apathy of housekeepers. It is time 
that they should bestir themselves for their own 
protection. A little knowledge of the right kind 
cannot hurt them, and it will surely bring a large 
return in comfort and economy. 

These mysterious chemicals are not so many 
or so complicated in structure but that a little 
patient study will enable any one to understand 
the laws of their action, so far as they apply to the 
common operations of the household. 

No attempt is here made to cover the whole 
ground of chemical science, but only to explain 
such of its principles as are involved in the raising 
of bread, and in a few other common processes. 



PREFACE 

To the Second Edition. 



THE science of chemistry has made rapid 
strides in the past fifteen years. Biological 
science has sprung from infancy to sturdy man- 
hood during the same time, and a knowledge of 
both with their relations to each other is necessary 
to the right understanding of the manifold opera- 
tions of life. All the sciences and all the arts are 
taxed by thej intelligent home-maker for the 
proper foundation and continuance of the complex 
life of the home. 

The establishment of more homes and their 
right conduct when established, which results in 
the better utilization of time, money and strength, 
means the perpetuity, prosperity and power of the 
nation. 

Without trespassing upon the domain of house- 
hold bacteriology, a knowledge of the chemistry 
of cooking and cleaning must include some dis- 
cussion of the sources of dirt, its composition and 
its dangers, and the discussion of methods for its 
removal, which shall at the same time be speedy, 
safe and effectual. 



vi PREFACE. 

Experience teaches that in domestic work there 
is no best rule of universal application. Circum- 
stances vary so widely that principles, alone, can 
be laid down. Each case requires a large propor- 
tion of judgment — a compound of more complex 
composition than any chemical substance ever 
dealt with. 

If any housekeeper finds a method better for 
her purpose than the one specified here, let her 
keep to its use and tell it to others. This work 
will have accomplished its purpose if it interests 
those who understand already the principles of 
cooking and cleaning; gives a few answers to 
those who continually ask "Why?" and "How?" 
and stimulates to study and thought the many 
who have long labored with willing hearts but 
with untrained minds and hands. 

Boston, 1897. 



CONTENTS. 



PAGE 

Preface to First Edition iii 

Preface to Second Edition v 

PART I. 

Introduction I 

I. Matter and Its Composition ... 5 

II. Elementary Chemistry 12 

III. Starches, Sugars, Fats, Their Preparation 

as Food . .24 

IV. Nitrogenous Constituents .... 47 

V. Flavors and Condiments. Diet ... 56 

• 
PART II. 

I. Dust . 71 

II. Dust Mixtures (Grease and Dust) . . 87 

III. Stains, Spots, Tarnish 100 

IV. Laundry 118 

V. Chemicals, and Their Use in the House- 

hold 145 

VI. Antiseptics, Disinfectants, Insecticidfs . 165 

Books of Reference 181 

Index . . . 183 



INTRODUCTION 

To the Revised Edition of 1907. 



IN the thirty years since this little book was 
written, the interpretation of many scientific 
facts has been changed as more facts have been 
discovered, and also, in many cases, the method 
of expressing the well-established facts has been 
changed to agree with newer theories. 

Although at first sight this seems discourag- 
ing, it should not prevent an attempt to under- 
stand some of the fundamental laws upon which 
every-day life and health depend. The author 
has already learned three different systems of 
expressing the same facts in chemistry and 
expects to learn yet another. 

In making this revision a medium course has 
been chosen. It is not prepared for the scien- 
tific man, but its mission is now, as it has been 
heretofore, to the average intelligent housewife. 
She needs to see that there are reasons for things 
in order to lift the monotonous operations of the 
kitchen in particular, and the household in gen- 



2 THE CHEMISTRY OF 

eral, from distasteful drudgery to a plane of 
intelligent direction of scientific processes, the 
results of which may be more or less controlled. 

It is this sense of control, of power to pro- 
duce desired results, which gives an interest to 
daily duties. Since the good health and earning 
capacity of the family depend upon the house- 
mother's knowledge of the laws which govern 
the daily making and baking and cleaning, surely 
it will be worth her while to try to absorb the 
spirit of modern scientific research, to observe 
what goes on in her pots and pans, to watch 
her oven, and especially to scrutinize her dish 
washing. 

Knowledge of foods and of chemical proc- 
esses is increasing so rapidly that what is written 
is out of date before the ink is dry, but a little 
more or less exact information is not so im- 
portant as that the spirit of inquiry, of open- 
mindedness, shall pervade all departments of 
household activity. 

Thirty years ago very few grown women had 
received any training in chemistry. Chemical 
nomenclature was worse than Greek to them. 
Today the majority of young housewives have a 
small remnant of school chemistry among their 
store of miscellaneous knowledge. It is to be 
feared that it is rather vague, but chemistry is 



COOKING AND CLEANING. 3 

not the bugbear it once was. The present day 
housewife is not afraid of chemical substances. 

The great difficulty in explaining chemical 
results has been in showing the law of definite 
proportions, that fundamental law, discovered 
by Dalton, in and upon which the whole theory 
has been built. 

The law of exchange of different quantities 
having different values not according to quan- 
tity, but according to value, has always been 
difficult to express. 

One reason for dwelling upon the law of defi- 
nite proportions is because the idea is so preva- 
lent that if the effect of a teaspoonful is good, 
that of a teaspoonful and a half is better, whereas 
the extra half may be the cause of failure. The 
long experience of a grocery clerk gives his hand 
nerves such a response to weight that he may 
dispense with scales in putting up a pound of 
sugar. In this way the skilled cook tells the 
proportions with the exactness of the balance, 
but woe betide the unskilled housewife who 
attempts the same trick. 

One other fact in relation to science, and chem- 
ical science in particular, must be borne in mind. 
While much is known, there remains much more 
still hidden. It is practical wisdom to use all 
that is known and to accept results as far as they 



4 THE CHEMISTRY OF 

prove beneficial, without waiting to learn all the 
reasons why. Not that the search for reasons 
should be abandoned, but that each bit of knowl- 
edge should be applied as fast as gained. 



THE CHEMISTRY OF COOKING 
AND CLEANING. 



CHAPTER I. 
Matter and Its Composition. 

WE give the name matter to the objects Matter 
which can be recognized by any one of 
our senses. There are many kinds of matter and 
many forms of one kind. Ice melts into water, 
water changes into steam. In our stoves, the 
hard, black coal disappears, leaving a soft, gray 
ash, that weighs much less than the original coal. 
Something has been taken away. 

The leaf is covered by wind-blown soil and Chang 
soon no leaf is there ; but the matter of which it 
was composed is still somewhere, for that is 
never lost. Living matter is in constant change 
from one form to another. Our bodies are com- 
posed of matter, and to their continued existence, 
as well as to their growth, material substances 
are necessary. Some changes come quickly, some 
slowly. Years, ages even, are sometimes neces- 
sary to bring about a result that is visible to us. 



es in 
Matter. 



6 THE CHEMISTRY OF 

A familiar substance, sugar, for example, may 
be subjected to different changes. Put two table- 
spoonfuls of white sugar into a scant half cup of 
water. The sugar disappears. The clear water 
changes to a syrupy liquid. If the water is 
allowed to evaporate slowly, the sugar is found 
to remain. 

A teaspoonful of sugar dropped upon the 
warm stove changes in character. There ap- 
pears a black mass, which is readily recognized 
as charcoal. 

Add a solution of an acid to a solution of an 
alkali, and observe that the acid substance and 
the alkaline substance are no longer in existence 
as such. There is, instead, a neutral saline sub- 
stance dissolved in water. The new substance 
has the properties of neither of the others. The 
acid and the alkali have lost their identity. 

Dissolve a teaspoonful of sugar in a cupful of 
water. Add a very little yeast and put the cup 
in a warm place. Soon bubbles of gas rise and 
break on the surface; while, on distilling the 
liquid, a new acquaintance presents itself in the 
form of alcohol. The first-mentioned change in 
the sugar — the solution of it in water — is a 
physical change; for the character of the sub- 
stance is not permanently altered. The second 
change — the charring — is a chemical change — 



COOKING AND CLEANING. 7 

the substance loses its individual character. The 
third change in the sugar — its fermentation — 
which is most important for our present purpose, 
is also a chemical change but one caused by the 
action of life. When the syrup ferments, we 
know that living organisms are at work in the 
solution, changing the substance by their own 
processes of growth. To this class, then, we may 
apply the name biological change. Here belong 
the changes in our own bodies which enable them 
to live and grow. Death comes when these 
" vital" changes can no longer proceed in a 
normal, healthy manner. 

Changes in matter, then, are of two kinds. 

I. Physical. Change of form, without per- 
manent loss of identity. This is brought about 
by outside forces : heat, blows, etc. 

II. Chemical. Complete change of character, 
with or without change of form. This is brought 
about by chemical agencies, by fire and electric- 
ity — also forces from without. 

Physical and chemical forces, working to- 
gether, allow biological results, caused by living 
cells producing energy by means of their life 
processes. 

Under these heads come the numerous changes 
which every housewife observes and which all 
should understand, so far as such understanding 
is necessary for the true economy of the house. 



THE CHEMISTRY OF 



Forms of 
Matter. 



We have seen that matter is subject to two 
kinds of change. Experience teaches that matter 
exists in three different forms — solids, liquids 
and gases. It teaches, also, that by the action of 
outside forces some solids become liquids and 
some liquids become gases. The reverse proc- 
ess, also, is known — gases change into liquids 
and liquids into solids. The chemist or physicist 
is able to change matter from one form into 
another in many more- instances than are ob- 
served in ordinary experience. 

What causes can be made to bring about these 
changes ? Before an iron kettle or stove can be 
made, the metal from which it is formed must 
be subjected to intense heat, when it will become 
a liquid and can be poured into molds of any 
desired shape. Solid ice melts or becomes water 
at a low temperature; but at a higher degree of 
temperature, the water becomes steam or gas. 
Some solids, as camphor and iodine, sublime, that 
is, pass directly into the gaseous form. 

Heat, then, is one influence which brings about 
a change of state in material substances. If heat 
be abstracted from a liquid, the latter may be- 
come a solid, as when water becomes ice. Like 
changes are less readily brought about by pres- 
sure, gases becoming liquids ; liquids becoming 
solids. Cold and pressure, acting together, are 



COOKING AND CLEANING. 9 

able to liquefy the air, and other gases once 
called permanent. 

Different degrees of heat produce varying Expansion, 
degrees of liquefaction. Sometimes only a semi- 
liquid state results, as in the melting of solder, 
of gelatine and of tar. Almost all matter (ex- 
cept water between 32 ° and 39 ° Fahrenheit) 
expands or occupies more space under the action 
of heat ; but in gases the proportion of expansion 
is much the greatest. This expansion of gases 
with heat makes possible the process of ventila- 
tion by means of an open fire, and is one factor 
in the rise of dough. 

The solids may also be changed to liquids. Solution. 
The degree of solubility of any substance de- 
pends largely upon the temperature of the solv- 
ent. Common salt dissolves nearly as well in 
cold as in warm water. "Soda" and alum dis- 
solve more readily in warm than in cold, while 
cream of tartar requires hot water for its com- 
plete solution. 

The amount of solid which water will dissolve Saturation, 
usually increases with the temperature to a cer- 
tain degree. After this no more will dissolve 
and the solution is " saturated." Gases readily 
dissolve in water, but usually in cold solutions 
only. 

The action of the liquid is more rapid if the 



10 



THE CHEMISTRY OF 



Solvents. 



Swelling. 



solid be first powdered, for a greater area is thus 
presented to the action of the liquid. It is also 
usually more rapid when the substance is placed 
upon or near the surface. Under these condi- 
tions each particle, while dissolving, is sur- 
rounded by a thin envelop of syrup, which be- 
comes heavier and sweeter. The film of syrup 
sinks into the solvent liquid, so that a clean sur- 
face is continually exposed to be acted upon. 
Solution is a valuable agent in bringing about 
chemical action during many processes of cook- 
ing and cleaning. 

Water is a nearly universal solvent. It dis- 
solves larger quantities of more substances than 
any other liquid. Some solids, however, dissolve 
more readily in other liquids, as camphor in alco- 
hol. Silver, copper and tin are not perceptibly 
dissolved in pure water, while most of their com- 
pounds, as nitrate of silver and sulphate of cop- 
per, are thus soluble. Lead dissolves more read- 
ily in pure water than in that containing some 
impurities. Gold may be dissolved in a warm 
mixture of two strong acids. Many of these 
metallic solutions which may be formed in cook- 
ing utensils and water pipes are poiscnous, and 
a knowledge of them becomes a matter of great 
importance to all housekeepers. 

A process of daily occurrence in the household 



COOKING AND CLEANING. 11 

greatly resembles solution. It consists in the 
taking up of water, which produces an increase 
of bulk or " swelling," but no true solution. Gel- 
atine swells in cold water and may then be dis- 
solved in hot water. Starch "jells" by taking 
up water; so we soak the cereals which consist 
largely of starch, that they may be more quickly 
acted upon by heat. 



M 



CHAPTER II. 

Elementary Chemistry. 

OST substances with which we deal in or- 
dinary life are compounds of two or more 
elementary constituents. The grain of wheat, 
the flesh of animals, the dangerous poison, are 
each capable of separation into simpler sub- 
stances. Finally a substance is found which can- 
not be further separated. A chemical clement 
is a substance which cannot be decomposed into 
other substances. 
Elements. Pure gold is an element from which nothing 

can be taken different from itself, but gold coin 
contains a little copper or silver or both. The 
oxygen of the air is an element. Air is a mix- 
ture of two or more elements. Oxygen and 
hydrogen, both gaseous elements, unite in cer- 
tain proportions to form the chemical compound, 
water. 

There are about eighty of these elements 
known to the chemist, while their compounds 
are infinite. For his convenience the chemist 
abbreviates the names of the elements into syn> 



COOKING AND CLEANING. 13 

bols, which he uses instead of the names. Usu- 
ally, the first or the first two letters of the Latin 
name are taken. These symbols mean much 
more, however, than time saved, as we shall see. 

Most of the elements unite with each other. Compounds. 
Then in the resulting compounds, one or more 
elements may be exchanged for others, so that a 
multitude of combinations are formed out of few 
elementary substances. The bulk of our food, 
clothing and furniture is made up of only five or 
six of these elements, although about twenty of 
them enter into the compounds used in the 
household. The others are found in nature, in 
the chemical laboratory or in the physician's 
medicine case. A few are so rare as to be con- 
sidered curiosities. 

Every housewife should understand something chemical Laws, 
of these chemical substances — their common 
forms, their nature and their reactions, that she 
may not be cheated out of time and money, and, 
more important still, that she may preserve the 
health of those for whom she cares. 

All chemical changes are governed by lazvs. 
Under like conditions, like results follow. No 
chemical sleight of hand can make one pound of 
washing soda do the work of two pounds, or one 
pound of flour make a third more bread at one 
time than at another, 



14 THE CHEMISTRY OF 

Pr<T P oJti<5 l e s finite One °^ tne most important of these laws is 
that known as the Laiv of Definite Proportions, 
which states that the various elements do not 
unite to form chemical compounds in any pro- 
portions whatever, but only in perfectly definite 
proportions. From this it follows that to the 
elements can be assigned values which represent 
the quantities of them which enter into combina- 
tion with each other. These values are called 
the combining weights or atomic weights of the 
elements, the latter term having been introduced 
since it is assumed that the elements are built up 
of extremely small particles of matter called 
atoms, and that compounds are made of groups 
of these atoms called molecules, and since under 
this assumption the relative weights of the ele- 
ments which unite represent the relative weights 
of the atoms or multiples of them. Thus, in the 
compound water, hydrogen and oxygen are 
present always in perfectly definite proportions, 
namely, in the relation of one part by weight of 
hydrogen to eight parts by weight of oxygen ; 
and in the compound acetylene, the elements 
carbon and hydrogen are always present in the 
proportion of one part of hydrogen to twelve 
parts of carbon. It is customary to adopt as the 
standard of reference one part by weight of 
hydrogen and to adopt as the combining weight 



COOKING AND CLEANING. 15 

or atomic weight of other elements that quantity 
of them which combines with one part of hydro- 
gen, or in some cases with two or more parts of 
this element. 

Upon this basis the atomic weight of oxygen 
is sixteen and that of carbon twelve times the 
atomic weight of hydrogen. The symbol of an 
element is made to represent its constant atomic 
weight ; so that, while the word oxygen means 
only the collection of properties to which is given 
the name, the symbol O indicates a definite quan- 
tity of oxygen which is sixteen times the weight 
of hydrogen represented by the symbol H. 

While it is always true that the elements com- Law of Multiple 
bine with each other only in definite proportions, 
yet it is often true that they combine to form two 
or more definite compounds. Such combinations 
are governed by the Law of Multiple Propor- 
tions: When elements form more than one com- 
pound, they unite according to some multiple of 
their combining weights. 

Thus, sulphur and oxygen form two difTerent 
compounds represented by- the symbols S0 2 and 
S0 3 — where the proportions of sulphur to oxy- 
gen are thirty-two to thirty-two for the first and 
thirty-two to forty-eight for the second, the com- 
bining weight corresponding to the symbol S 
being thirty-two. 



Proportions. 



16 THE CHEMISTRY OF 

A partial list of atomic weights is as follows: 



Element. 


Symbol. 


At. weight. 


Element. Symbol. 


At. weight. 


Aluminum 


Al 


» 27.I 


Magnesium 


Mg 


24.36 


Calcium 


Ca 


40.I 


Nitrogen 


N 


14.04 


Carbon 


C 


I2.0 


Oxygen 


O 


16.O 


Chlorine 


CI 


35-45 


Phosphate 


P 


31.O 


Copper 


Cu 


63.6 


Potassium 


K 


39-15 


Gold 


Au 


197.2 


Radium 


Ra 


225.O 


Hydrogen 


H 


1.008 


Silicon 


Si 


28.4 


Iodine 


I 


126.97 


Silver 


Ag 


I07-93 


Iron 


Fe 


55-9 


Sodium 


Na 


23-05 


Lead 


Pb 


206.9 


Sulphur 


S 


32.06 


Lithium 


Li 


7-03 


Zinc 


Zn 


654 



Symbols. Tri e symbols, then, are the chemist's shorthand 

alphabet, or his sign language. The non-scien- 
tific reader is apt to look upon the acquisition of 
this sign language as the schoolboy regards the 
study of Chinese — as the work of a lifetime. He 
would be near the truth were he to attempt to 
remember the symbols of all the complicated 
compounds known and constantly increasing; 
but a study of the properties and combinations 
of the few which make the common substances 
of daily use need not frighten the most busy 



COOKING AND CLEANING. 17 

housewife, for they can be comprehended in a 
few hours of thoughtful reading. Then a little 
practice will make them as familiar as the recipe 
of her favorite cake. "To master the symbolical 
language of chemistry, so as to fully understand 
what it expresses, is a great step toward master- 
ing the science." 

The exchanges and interchanges among the Reactions, 
elements by which new compounds are produced 
are called chemical reactions. The written ex- 
pression of the reaction is called a chemical 
equation. In all chemical equations there is just 
as much weight represented on one side of the 
sign of equality ( = ) as on the other. 

C + 2 = co 2 

12 + 32 = 44 
Carbon. Oxygen. Carbon Dioxide. 

HC1 + NaOH = NaCl + H 2 

Hydro- Sodium Sodium Water, 

chloric Hydrate. Chloride, 

Acid. or Com- 

mon Salt. 

36.5 + 40 = 58.5 + 18 
76.5 = 76.5 

This shows that the sum of the weights of 
the two substances taken is equal to the sum of 
the weights of the new substances formed as the 
result of the reaction. 



18 THE CHEMISTRY OF 

It is this exactness in dealing with matter 
which gives to the study of chemistry its great 
value from an educational standpoint. In the 
economy of nature nothing is lost. Wood and 
coal burn in our stoves. The invisible product 
of their combustion, C0 2 , passes into the air, but 
adds a definite amount to the weight of the air. 
Thus the symbol of this product shows that 
twelve pounds of coal (which when free of ash 
is nearly pure carbon) in burning take from the 
air thirty-two pounds of oxygen and give back 
to the air forty-four pounds of carbon dioxide. 

Similarly the symbol of water, H 2 (atomic 
weights, H = I, O = 16), shows that for every 
eighteen parts by weight of water produced, 
there will be two parts by weight of H and six- 
teen parts by weight of O required. 

Although the phenomena themselves are found 
to be unchangeable, our explanation of them may 
be modified as our knowledge increases. 

Present theories penetrate only a little into the 
real essence of things, and the investigator soon 
stumbles upon questions whose explanation does 
not at present even seem to be a possibility. 

(See late text-books on chemistry for the dif- 
ference between ions and atoms.) 
Oxidation. One of the most important chemical changes 

that takes place inside or outside the animal body 



COOKING AND CLEANING. 10 

is that union of oxygen (four-fifths of the air) 
with carbon or hydrogen which we call oxida- 
tion — under. the steam boiler and in the stove it 
is called combustion. It is the chief source of 
available power or energy in either case. (See 
pp. 25, 26.) 

The same amount of heat is evolved when a 
given amount of. substance is oxidized, whether 
the combustion takes place slowly or rapidly. 

An appreciation of these fundamental laws of The 

i-i 1 • • 11 »• 1 Calorimeter. 

chemical combination is needed to realize the 
significance of the recent work on the use of 
food in the human body as demonstrated in the 
calorimeter. 

Before a study of the chemical composition of 
food materials and of the chemical and physical 
changes occurring in the processes of cooking 
as a preparation for the best utilization of these 
food stuffs could be insisted upon, it was neces- 
sary to be convinced that the utilization of the 
chemical compounds, such as sugar, starch, albu- 
min, etc., was the same in effect within the body 
as without, in stove or furnace. 

For the proof that the law of the conserva- 
tion of energy held in the life processes going 
on in the human body, an examination of the 
food and of the results of its consumption was 
imperative. 



20 THE CHEMISTRY OF 

For this purpose a " respiration calorimeter" 
was set-up.* 

"This is a metal-walled chamber in which- a 
man lives, eats, drinks, works and sleeps. Pro- 
vision is made for ventilating the chamber and 
for regulating the temperature and moisture of 
the air within it. The volume of the ventilating 
air current is measured and samples for analysis 
are taken before and after it passes through the 
chamber, thus obtaining the amounts of carbon 
dioxide and water in the respiratory products. 
The food, drink, feces and urine are weighed 
and analyzed, and their potential energy is deter- 
mined, as is the kinetic energy given off from the 
body in the forms of heat and external muscular 
work. 

"The devices for measuring the heat or loss 
of heat given off from the body include : ( I ) 
Arrangements to prevent gain or loss of heat 
in the chamber either by the passage of heat 
through the walls or the bringing in and taking 
out of heat in the ventilating air current; (2) 
arrangements by which the heat given off in the 
chamber, by the body or otherwise, is carried 
out by a current of water. . . . This current, 
which is conveyed by copper pipes, comes into 
the chamber at a low temperature, passes around 
the interior, absorbs the heat, and goes out cor- 
respondingly warmer. The quantity of the water 
and the rise of temperature show how much heat 
is carried out." 

*" Description of a New Respiration Calorimeter and Experiments on 
the Conservation of Energy in the Human Body," by W. O. Atwater, Ph.D; ; 
Professor of Chemistry, Wesleyan University, and E. B. Rose, Ph.D., Pro- 
fessor of Physics, Wesleyan University. 



COOKING AND CLEANING. 21 

By means of such apparatus there may be de- J/^jg 11 Value 
termined questions pertaining to the demands Ex P erim ents. 
of the body for nutriment under different condi- 
tions of work and rest ; the duties performed by 
the different nutrients of food in supplying the 
needs of the body; and finally the nutritive 
values of food materials and the amount and 
proportions best adapted to the needs of people 
of different classes, with different occupations 
and in different conditions of life. 

By experiment it has been found that I gram 
of carbohydrates (starch, sugar, etc.) or proteids 
(lean meat, white of egg, etc.) gives on an aver- 
age about 4.1 calories,* and one gram of fats 9.3 
calories. Therefore to find the value of a given 
dish set upon the family table is simple when 
the weights of the ingredients are known. For 
instance, in a curry stew with rice, three pounds 
of medium fat beef will yield 259 grams proteid 
and 175 grams of fat, while ten ounces of rice 
will yield 22.5 grams proteid, 1 gram of fat and 
222 grams of carbohydrates. Adding together 
the carbohydrate and proteid gives 503.5 grams. 
Multiplying this number by the 4.1 calories per 
gram we have 2,064 calories; while multiplying 
the 176 grams of fat by 9.3 gives 1,636 calories 
for the fat, a total of 3,700 calories, or as many 

* For definition of calories, see page 47. 



22 THE CHEMISTRY OF 

as should be supplied by a dinner for three 
working men. 

The housewife well understands that she may 
provide sufficient food, but that she cannot be 
sure it will be eaten, or assimilated if it is eaten. 
But she must also understand that power does 
not come from nothing, and that if sufficient 
nourishment is not provided, the body cannot 
have its full due. 
iwifrs One °^ ^ le un i versa l chemical operations in 

the household is the use of cream of tartar and 
baking soda or of baking powders. Advantage 
has been taken of this fact to put upon the 
market many substitutes and variations with the 
natural result that the housewife is confused and 
uncertain. The table on page 23 may be helpful 
in clearing up some of the mysterious ways of 
the substances themselves and of their advocates. 

Thus, 84 parts of cooking soda unite with 188 
parts of cream of tartar — if both are pure — to 
give 44 parts of the gas C0 2 . Cream of tartar 
is a compact powder, however, so that a tea- 
spoonful will weigh more than a teaspoonful of 
soda, and illustrates the difference in accuracy 
between weighing and measuring. Because 
cream of tartar is so liable to cake, a starch is 
added to the mixing for baking powder. For 
home preparation 5 to 10 per cent will be enough. 



COOKING AND CLEANING. 23 

§x|l§ 

« 53 + + + + 

CO ^"^ 

4 S S K ~ Ph 



+ o o 

o i x K 



CI 

,- O k ffi js w , 

8 » B Si ! s * 

I + * Q + 5 






o 



a 



+ 1-H K> C/2 . w OO 

%** Ui l*i i ! 



£ o ^ o 

^X © ^°° -3 

K w ffi X o 

<0 * 



CHAPTER III. 



Living and 

Lifeless 

Matter. 



Chemical 
Change 
Produces 
Heat. 



Starches, Sugars, Fats, Their Preparation for Food. 

THE material world is divided into living and 
lifeless matter. All living matter requires 
food that it may grow, repair waste, and reproduce 
itself, if the existence of its kind is to be continued. 
This food must be made from the material elements 
we have been studying. Food for the human body 
must, therefore, contain such elements, in com- 
bination, as are found in the body substance, in 
order that new materials may be formed from 
them by the processes of life. 

Wherever there is life, there is chemical change, 
and, as a rule, a certain degree of heat is neces- 
sary, in order that chemical change may occur. 
Vegetation does not begin in the colder climates 
until the air becomes warmed by the heat of the 
spring. When the cold of w T inter comes upon 
the land, vegetation ceases. If plant life is to be 
sustained during a northern winter, artificial 
warmth must be supplied. This is done by heat 
from a furnace or stove. In chemical terms, car- 
bon and hydrogen from coal, wood, or gas are 
caused to unite with the oxygen of the air to form 
carbon dioxide (carbonic acid gas) and water, and 



COOKING AND CLEANING. 25 , 

by this union of two elements with oxygen, heat 
is produced. 

c +o 2 =c o 2 

C H 4 +O4 =C 2 +2H 2 O 

These two chemical reactions indicate the Combustion, 
changes which cause the production of artificial 
heat generally used for domestic purposes. All 
living matter, whether plant or animal, is found 
by analysis to contain carbon, oxygen, hydrogen, 
and nitrogen. Other elements are present in small 
and varying quantities, but "the great four" are 
the essentials. The plant is able to take all its 
food elements from air, water and soil, and, in 
its own cells, to manufacture those compounds 
upon which it can feed ; while an animal cannot do 
this, but must accept for the most part the manu- 
factured product of the plant. Man, therefore, 
finds his food in both vegetable and animal sub- 
stances. 

Since many animals live in temperatures in 
which plants would die, it is evident that they must 
have some source of heat in themselves. This is 
found in the union of the oxygen of the air 
breathed, with carbonaceous matter eaten as food, 
and the formation of carbonic acid gas (carbon 
dioxide), and water (C0 2 and H 2 0), just as 
in the case of the combustion of the wood in the 
grate. Only, instead of this union taking place in 



26 



THE CHEMISTRY OF 



Vital Tem- 
perature. 



Food Elements 
for Combus- 
tion. 



Oxygen. 



one spot, and so rapidly as to be accompanied by 
light, as in the case of the grate fire, it takes place 
slowly and continuously in each living cell. 
Nevertheless, the chemical reaction seems to be 
identical. 

The heat of the human body must be main- 
tained at 37 C — the temperature necessary for 
the best performance of the normal functions. Any 
continued variation from this degree of heat indi- 
cates disease. Especially important is it that there 
be no considerable lowering of this temperature, 
for a fall of one degree is dangerous. 

The first requirement of animal life is, then, the 
food which supplies the heat necessary for the 
other chemical changes to take place. The class 
of foods which will be considered here as those 
utilized for the production of animal heat among 
other functions, includes the carbon compounds, 
chiefly composed of carbon, hydrogen and oxygen. 

The slow combustion or oxidation of these car- 
bonaceous bodies cannot take place without an 
abundance of oxygen; hence, the diet of the ani- 
mal must include fresh air — a point too often over- 
looked. The amount of oxygen, by weight, taken 
in daily, is equal to the sum of all the other food 
elements. One-half of these consists of some form 
of starch or sugar — the so-called carbohydrates, 



COOKING AND CLEANING. 27 

in which the hydrogen and oxygen are found in 
the same proportions as in water. (The fats will 
be considered by themselves.) 

Starches, sugars and gums are among the con- starches, 
stituents of plants, and are sometimes found in 
animals in small quantities. Starch is found in 
greater or less abundance in all plants and is laid 
up in large quantities in the seeds of many species. 
Rice is nearly pure starch, wheat and the other 
cereals contain sixty to seventy per cent of it. 
Some tubers contain it, as potatoes, although in 
less quantity, ten to twenty per cent. It is formed 
by means of the living plant-cell and the sun's 
rays, from the carbon dioxide and water contained 
in the air, and it is the end of the plant life — the 
stored energy of the summer, prepared for the 
early life of the young plant another year. An 
allied substance is called cellulose. This oc- 
curs under numerous forms, in the shells 
and skins of fruits, in their membraneous 
partitions, and in the cell walls. Starch in its com- 
mon forms is insoluble in water. It dissolves par- 
tially in boiling water, forming a transparent jelly 
when cooled. 

Sugars, also, are a direct or indirect product of sugars, 
plant life. Common sugar, or cane-sugar, occurs 
in the juices of a few grasses, as the sugar-cane; 
of some trees; and of some roots. Milk-sugar is 



28 THE CHEMISTRY OF 

found in the milk of mammalia, while grape-sugar 
is a product of the ripening processes in fruit. 
Solution 11 " Digestion is primarily synonymous with solu- 

tion. All solid food materials must become prac- 
tically soluble before they can pass through the 
walls of the digestive system. As a rule, non-crys- 
talline bodies are not diffusible, so that starch and 
like materials must be transformed into soluble, 
crystalline substances, before absorption can take 
place. Cane-sugar, too, has to undergo a chemical 
change before it can be absorbed; but grape and 
milk sugars are taken directly into the circula- 
tion. To this fact is due a part of the great nu- 
tritive value of dried fruits as raisins, dates and 
figs, and the value of milk-sugar over cane-sugar, 
for children or invalids. Chemically pure milk- 
sugar can now be obtained at wholesale for about 
35 cents per pound. This may be used in certain 
diseases when cane-sugar is harmful. The chemi- 
cal transformations of starch and sugar have been 
very carefully and scientifically studied with refer- 
ence to brewing and wine-making. Several of the 
operations concerned necessitate great precision in 
respect to temperature and length of time, and 
these operations bear a close analogy to the 
process of bread-making by means of yeast. The 
general principles on which the conversion of 
starch into sugar, and sugar into alcohol, are con- 



COOKING AND CLEANING. 29 

ducted will therefore be stated as preliminary to a 
discussion of starch and sugar as food. 

There are two distinct means known to the starch Con- 

version. 

chemist, by which this change can be produced. 
One is by the use of acid and heat, which changes 
the starch into sugar, but can go no farther. The 
other is by the use of a class of substances called 
ferments, some of which have the power of chang- 
ing the starch into sugar, and others of changing 
the sugar into alcohol and carbon dioxide. These 
ferments are in great variety and the seeds of 
some of them are always present in the air. Among 
the chemical substances called ferments, one is 
formed in sprouting grain which is called diastase 
or starch converter, which first, under the in- 
fluence of warmth, changes the starch into a sugar, 
as is seen in the preparation of malt for brewing. 
The starch (C 6 H 10 O 5 ), first takes up water (H 2 0), 
and, under the influence of the ferment, is changed 
into maltose. Cane-sugar is readily converted 
into two sugars, dextrose and levulose, belonging 
to the glucoses. 

Ci, H 22 On +H 2 O +ferment=2Ce <H ia O c 

Cane-Sugar. Water. Dextrose and Levulose. 

Glucose and maltose are converted by yeast into Sugar 

Conversion. 

alcohol and carbon dioxide. In beer, the alcohol 
is the product desired, but in bread-making the 



30 THE CHEMISTRY OF 

chief object of the fermentation is to produce car- 
bon dioxide to puff up the bread, while the al- 
cohol escapes in the baking. 



{2C, H 6 O 
Alcohol. 
2C 2 
Carbon Dioxide. 



Ce 

Dextrose 



The alcohol, if burned, would give carbon dioxide 
and water. 

2C 2 H 6 O +12O =4C 2 +6H2 O. 

Alcohol. Oxygen. Carbon Dioxide. Water. 

It will be seen, from the previous equations, 
that nothing has been lost during the process. 
The six atoms of carbon in the original starch 
reappear in the carbon dioxide at the end, 
2C0 2 -r-4C0 2 . Two atoms of hydrogen from the 
water, and thirteen atoms of oxygen from the 
water and the air have been added. Reckoning 
the atomic weights of the starch used, the carbon 
dioxide and the water formed, we find that, in 
round numbers, sixteen pounds of starch will yield 
twenty-six pounds of gas and ten pounds of water, 
or more than double the weight of the starch. 
These products of decomposition are given back 
to the air in the same form in which those sub- 
stances existed from which the starch was orig- 
inally formed. 
i?th V e ersion The same cycle of chemical changes goes on in 

Digestive ^ h uman body when starchy substances are 



COOKING AND CLEANING. 31 

taken as food. Such food, moistened and warmed 
in the mouth, becomes mixed with air through 
mastication, by reason of the property of the sa- 
liva to form froth, and also becomes impregnated 
with ptyalin, a substance which can change starch 
into sugar as can the diastase of the malt. The 
mass then passes into the stomach, and the 
change, once begun, goes on. As soon as the 
sugar is formed, it is absorbed into the circu- 
latory system and, by the life processes, is oxi- 
dized, i. e., united with more oxygen and changed 
finally into carbon dioxide and water. 

No starch is utilized in the human system as 
starch. It must undergo transformation before it 
can be absorbed. Therefore starchy foods must 
not be given to children before the secretion of 
the starch converting ferments has begun, nor to 
any one in any disease where the normal action of 
the glands secreting these ferments is interrupted. 
Whatever starch passes out of the stomach 
unchanged, meets a very active converter in 
the intestinal juice. If grains of starch escape 
these two agents, they leave the system in the 
same form as that in which they entered it. 

Early man, probably, lived much like the beasts, 
taking his food in a raw state. Civilized man re- 
quires much of the raw material to be changed, by 
the action of heat, into substances more palatable 
and already partly digested. 



32 THE CHEMISTRY OF 

The chemistry of cooking the raw materials is 
very simple. It is in the mixing of incongruous 
materials in one dish or one meal that complica- 
tion arises. 
5 h sur°ch king Since fully one-half of our food is made up of 

starches and sugars, it is pertinent to examine, 
beside their chemical composition, the changes 
which they may undergo in the processes of cook- 
ing that can render them more valuable as food, 
or which, on the other hand, may in large meas- 
ure destroy their food value. 

The cooking of starch, as rice, farina, etc., re- 
quires little explanation. The starch grains are 
prepared by the plant to keep during a season of 
cold or drought and are very close and compact; 
they need to be swollen and distended by moisture 
in order that the chemical change may take place 
readily, as it is a law, that the finer the particles, 
the sooner a given change takes place, as has 
been explained in a previous chapter. Starch 
grains may increase to twenty-five times their bulk 
during the process of hydration. 

The cooking of the potato and other starch-con- 
taining vegetables, is likewise a mechanical proc- 
ess very necessary as a preparation for the chem- 
ical action of digestion; for raw starch has been 
shown to require a far longer time and more di- 
gestive power than cooked starch. Change takes 



COOKING AND CLEANING. 33 

place slowly, even with thorough mastication, un- 
less the starch is heated and swollen, and, in case 
the intestinal secretion is disturbed, the starch 
may not become converted at all. 

The most important of all the articles of diet Bread, 
which can be classed under the head of starchy 
foods is bread. Wheat bread is not all starch, but 
it contains a larger percentage of starch than of 
anything else, and it must be discussed under this 
topic. Bread of some kind has been used by man- 
kind from the first dawn of civilization. During 
the earlier stages, it consisted chiefly of powdered 
meal and water, baked in the sun, or on hot 
stones. This kind of bread had the same charac- 
teristics as the modern sea-biscuit, crackers and 
hoe-cake, as far as digestibility was concerned. It 
had great density, it was difficult to masticate, 
and the starch in it presented but little more sur- 
face to the digestive fluids than that in the hard 
compact grain, the seed of the plant. 

Experience must have taught the semi-civilized 
man that a light porous loaf was more digestible 
than a dense one. Probably some dough was ac- 
cidentally left over, yeast plants settled upon it 
from the air, fermentation set in, and the possibil- 
ity of porous bread was thus suggested. 

The small loaf, light, spongy, with a crispness 
and sweet, pleasant taste, is not only aesthetically, 



34 THE CHEMISTRY OF 

but chemically, considered the best form in which 
starch can be presented to the digestive organs. 
The porous condition is desired in order that as 
large a surface as possible shall be presented to 
the action of the chemical converter, the ptyalin 
of the saliva, and, later, to other digestive fer- 
ments. There is also a better aeration in the proc- 
ess of mastication. 

The ideal bread for daily use should fulfill cer- 
tain dietetic conditions : 

i. It should retain as much as possible of the 
nutritive principles of the grain from which it is 
made. 

2. It should be prepared in such a manner as to 
secure the complete assimilation of these nutri- 
tive principles. 

3. It should be light and porous, so as to allow 
the digestive juices to penetrate it quickly and 
thoroughly. 

4. It should be especially palatable, so that one 
may be induced to eat enough for nourishment. 

5. It should be nearly or quite free from coarse 
bran, which causes too rapid muscular action to 
allow of complete digestion. This effect is also 
produced when the bread is sour. 

Ordinary Graham bread, brown bread and the 
black bread of Germany fulfill conditions 1 and 4, 
but fail in the other three. Bakers' bread of fine 



COOKING AND CLEANING. 35 

white flour fulfills 2, 3 and 5, but fails in the other 
two. Home-made bread often fulfills conditions 
4 and 5, but fails in the other three. 

Very early in the history of the human race Y^f. n ° r 
leavened bread seems to have been used. This was 
made by allowing flour and water to stand in a 
warm place until fermentation had well set in. A 
portion of this dough was used to start the process 
anew in fresh portions of flour and water. This 
kind of bread had to be made with great care, for 
germs different from yeast might get in, forming 
lactic acid — the acid of sour milk — and other sub- 
stances unpleasant to the taste and harmful to the 
digestion. 

Butyric acid occurs in rancid butter and in many 
putrified organic substances. A sponge made from 
perfectly pure yeast and kept pure may stand for a 
long time after it is ready for the oven and still 
show no sign of sourness. 

On account of the disagreeable taste of leaven 
and because of the possibility that the dough might 
reach the stage of putrid fermentation, chemists 
and physicians sought for some other means of 
rendering the bread light and porous. The search 
began almost as soon as chemistry was worthy the 
name of a science, and one of the early patents 
bears the date 1837. Much time and thought have 
been devoted to the perfecting of unfer- 



36 THE CHEMISTRY OF 

merited bread; but since the process of beer- 
making has been universally introduced, yeast has 
been readily obtained, and is an effectual means of 
giving to the bread a porous character and a pleas- 
ant taste. Since the chemistry of the yeast fer- 
mentation has been better understood, a change of 
opinion has come about, and nearly all scientific 
and medical men now recommend fermented bread. 
The bacteriology of bread and bread-making is 
yet somewhat obscure. The ordinary yeasts are so 
mingled with bacteria that the part which each 
plays is not yet understood. Only experiments 
long continued will solve these problems. 
S^°S Re " The chemical reactions concerned in bread- 

raising are similar to those in beer-making. To 
the flour and warmed water is added yeast, a mi- 
croscopic plant, capable of causing the alcoholic 
fermentation. The yeast begins to act at once, but 
slowly; more rapidly if sugar has been added and 
the dough is a semi-fluid. Without the addition 
of sugar no change is evident to the eye for some 
hours, as the fermentation of sugar from starch, by 
the diastase, gives rise to no gaseous products. As 
soon as the sugar is decomposed by the yeast plant 
into alcohol and carbonic acid gas (carbon diox- 
ide), the latter product makes itself known by the 
bubbles which appear and the consequent swelling 
of the whole mass. 



actions in 

Bread-Mak. 

ing. 



COOKING AND CLEANING. 37 

It is the carbon dioxide which causes the sponge- 
like condition of the loaf by reason of the peculiar 
tenacity of the gluten, one of the constituents of 
wheat. It is a well-known fact that no other kind 
of grain will make so light a bread as wheat. It is 
the right proportion of gluten (a nitrogenous sub- 
stance to be considered later) which enables the 
light loaf to be made of wheat flour. 

The production of carbon dioxide is the end of 
the chemical process. The rest is purely mechanical. 
The kneading is for the purpose of rendering the 
dough elastic by the spreading out of the already 
fermented mass and its thorough incorporation 
with the fresh flour. Another reason for kneading 
is, that the bubbles of gas may be broken up into 
as small portions as possible, in order that there 
may be no large holes, only very fine ones, 
evenly distributed through the loaf, when it is 
baked. 

The temperature at which the dough should be Temperature 
maintained during the chemical process is an im- Making, 
portant point. If the characteristics of "home- 
made" bread are desired, it is found to be better to 
use a small amount of yeast and to keep the dough 
at a temperature from 55 degrees to 60 degrees for 
twelve to fifteen hours, than to use a larger quantity 
of yeast and to cause its rapid growth. The changes 
which produce the desired effect are not fully under- 



38 THE CHEMISTRY OF 

stood. Above 90 degrees the production of acetic 
acid — the acid of vinegar — is liable to occur: for 
this temperature, while unfavorable for the yeast 
plant, is favorable for the growth of the particular 
bacterium which produces acetic acid. 

C 2 H 6 O +0 2 =C 2 H 4 2 +H 2 O 

Alcohol. Acetic Water. 

Acid. 

After the dough is stiffened by a little fresh flour 
and is nearly ready for the oven, the temperature 
may be raised, for a few minutes, to 100 degrees 
or 165 degrees F. The rapid change in the yeast is 
soon stopped by the heat of the oven. 
Bailng ' The baking of the loaf has for its object to kill 

the ferment, to heat the starch sufficiently to render 
it easily soluble, to expand the carbon dioxide and 
drive off the alcohol, to stiffen the gluten, and to 
form a crust which shall have a pleasant flavor. 
The oven must be hot enough to raise the tempera- 
ture of the inside of the loaf to 212 degrees F., or 
the bacteria will not all be killed. A pound 
loaf, four inches by four by nine, may 
be baked three-quarters of an hour in an 
oven where the initial temperature is 400 
degrees F., or for an hour and a half, where 
the temperature during the time does not rise above 
350 degrees F. Quick baking gives a white loaf, 
because the starch has undergone but little change. 



COOKING AND CLEANING. 39 

The long, slow baking gives a yellow tint, with the 
desirable nutty flavor, and crisp crust Different 
flavors in bread are supposed to be caused by the 
different varieties of yeast used or by bacteria, 
which are present in all doughs, as ordinarily 
prepared. 

The brown coloration of the crust, which gives 
a peculiar flavor to the loaf, is caused by the forma- 
tion of substances analogous to dextrine and cara- 
mel, due to the high heat to which the starch is 
subjected. 

One hundred pounds of flour are said to make 
from 126 to 150 pounds of bread. This increase of 
weight is due to the incorporation of water, pos- 
sibly by a chemical union, as the water does not 
dry out of the loaf, as it does out of a sponge. The 
bread seems moist when first taken from the oven, 
and dry after standing some hours, but the weight 
will be found nearly the same. It is this probable 
chemical change which makes the difference, to 
delicate stomachs, between fresh bread and stale. A 
thick loaf is best when eaten after it is twenty-four 
hours old, although it is said to be "done" when 
ten hours have passed. Thin biscuits do not show 
the same ill effects when eaten hot. The bread 
must be well baked in any case, in order that the 
process of fermentation may be stopped. If this be 
stopped and the mastication be thorough, so that 



40 



THE CHEMISTRY OF 



Expansion of 
Water into 
Steam. 



Methods of 
Obtaining i 

Carbon dioxide. 



the bread is in finely divided portions instead of in 
a mass or ball, the digestibility of fresh and stale 
bread is about the same. 

The expansion of water or ice into seventeen 
hundred times its volume of steam is sometimes 
taken advantage of in making snow-bread, water- 
gems, etc. It plays a part in the lightening of 
pastry and crackers. Air, at 70 degrees, doubles 
its volume at a temperature of 560 F., so that if air 
is entangled in a mass of dough, it gives a certain 
lightness when the whole is baked. This is the 
cause of the sponginess of cakes made with eggs. 
The viscous albumen catches the air and holds it, 
even when it is expanded, unless the oven is too 
hot, when the sudden expansion is liable to burst 
the bubbles and the cake falls. 

As has been said, the production of the porous 
condition, by means of carbon dioxide, generated 
in some other way than by the decomposition of 
starch, was the study of practical chemists for some 
years. 

A simple method for obtaining the carbon diox- 
ide is by heating bicarbonate of sodium. 



2Na H C O3 +heat = Na 2 C Os -fH 2 O +C O, 



The bicarbonate splits up into sodium carbonate, 
water, and carbon dioxide. The bread is light but 
yellow. Some of the carbonate remains in the 



COOKING AND CLEANING. 41 

bread, and as it neutralizes the acid of the gastric 
juice, digestion may be retarded. It also acts upon 
the gluten producing an unpleasant odor. 

Among the first methods proposed was one un- 
doubtedly the best theoretically, but very difficult 
to put in practice, viz., the liberation of carbon 
dioxide from bicarbonate of sodium by means of 
muriatic acid. 

Na H C 3 +H CI =Na CI +H 2 O +C 2 

" Soda." Hydrochloric Common Water. Carbon dioxide. 

Acid. Salt. 

This liberation of gas is instantaneous on the con- 
tact of the acid with the "soda," and only a skilled 
hand can mix the bread and place it in the oven 
without the loss of much of the gas. Tartaric acid, 
the acid phosphates, sour milk (lactic acid), vinegar 
(acetic acid), alum — ail of which have been used — 
are open to the same objection. Cream of tartar 
is the only acid substance commonly used which 
does not liberate the gas by simple contact when 
cold. It unites with "soda" only when heated, be- 
cause it is so slightly soluble in cold water. For the 
even distribution of the gas by thorough mixing, 
cream of tartar would seem to be the best ; but as, 
beside gas, there are other products which remain 
behind in the bread in the case of all the so-called 
baking powders, the healthfulness of these residues 
must be considered. 



42 THE CHEMISTRY OF 

Common salt is the safest, and perhaps the resi- 
dues from acid phosphate are next in order. 

The tartrate, lactate and acetate of sodium are 
not known to be especially hurtful. As the im- 
portant constituent of Seidlitz powders is Rochelle 
salt, the same compound as that resulting from the 
use of cream of tartar and "soda," it is not likely to 
be very deleterious, taken in the small quantities 
in which even habitual "soda biscuit'' eaters take it. 
products ^ ie var i° us products formed by the chemical de- 

composition of alum and "soda" are possibly the 
most injurious, as the sulphates are supposed to be 
the least readily absorbed salts. Taking into con- 
sideration the advantage given by the insolubility 
of cream of tartar in cold water, and the compara- 
tively little danger from its derivative — Rochelle 
salt — it would seem to be, on the whole, the best 
substance to add to the soda in order to liberate 
the gas; but the proportions should be chemically 
exact, in order that there be no excess of alkali to 
hinder digestion. Hence, baking powders pre- 
pared by weight and carefully mixed, are a great 
improvement over cream of tartar and "soda" 
measured separately. As commonly used, the 
proportion of soda should be a little less than 
half. The table on page 23 gives the chemical re- 
actions of the more common baking powders. 



COOKING AND CLEANING. 



43 



Fats. 

Another group of substances which, by their 
slow combustion or oxidation in the animal body, 
yield carbon dioxide and water and furnish heat 
to the system, is called fats. These comprise the 
animal fats — suet, lard, butter, etc. — and the vege- 
table oils — olive oil, cottonseed oil, the oily matter 
in corn, oats, etc. 

Fats, ordinarily so called, are simply solidified 
oils, and oils are liquid fats. The difference be- 
tween them is one of temperature only ; for, within 
the body, all are fluid. In this fluid condition, they 
are held in little cells which make up the fatty 
tissues. 

These fatty materials all have a similar composi- 
tion, containing, when pure, only carbon, hydro- 
gen, and oxygen. They differ from starch and 
sugar in the proportion of oxygen to the carbon 
and hydrogen, there being very little oxygen rela- 
tively in the fatty group, hence more must be 
taken from the air for their combustion. 



Composition 
of Fats. 



Cl8 H36 O2 

Stearic Acid in Suet. 



Ce H10 Os 

Starch. 



One pound of starch requires one and two-tenths 
pounds of oxygen, while one pound of suet re- 
quires about three pounds of oxygen for perfect 
combustion. This combination of oxygen with the 



Combustion 
of Fats. 



44 THE CHEMISTRY OF 

excess of hydrogen, as well as with the excess of 
carbon results in a greater quantity of heat from 
fat, pound for pound, than can be obtained from 
starch or sugar. Recent experiments have proved 
that the fats yield more than twice as much heat as 
the carbohydrates; hence people in Arctic regions 
require large amounts of fat, and, everywhere, the 
diet of winter should contain more fat than that of 
summer. 
Sources of While the chemical expression of these changes 

is that of heat produced, it must be remembered 
that energy or work done by the body is included, 
and that both fats and carbohydrates are the source 
of this energy, and that they must be increased in 
proportion as the mechanical work of the body in- 
creases. If a quantity is taken at any one time 
greater than the body needs for its work, the sur- 
plus will be deposited as a bank account, to be 
drawn from in case of any lack in the future supply 
of either. 

This double source of energy has a large 
economic value, for it has been noticed that in com- 
munities where fats are dear, the required amount 
of heat-giving and energy-producing food is made 
up by a larger proportion of the cheaper carbo- 
hydrates. This prevents too large a draft on the 
bank account. It has also been noticed that wage- 
earners do use a large proportion of fat, whenever 
it is within their means, 



COOKING AND CLEANING. 45 

Numerous investigations into the condition of ?a t c " s t he of 
the insane, as well as of the criminal classes, show Diet - 
the results of too little nutrition and the absence of 
sufficient fat. The diet of school children should 
be carefully regulated with the fat supply in view. 
Girls, especially, show, at times, a dislike to fat and 
an overfondness for sugar. They should have the 
proper proportion of fat furnished by butter, cream, 
or, if need be, in disguised form. The cook must 
remember that the butter absorbed from her cake 
tin or the olive oil on her salad is food, as well as 
the flour and eggs. 

The essential oils, although very important, as 
will be shown in the chapter on flavors, occur in 
such small quantities that they need not be con- 
sidered here, except by way of caution. These oils 
are all volatile, and, therefore, will be dissipated by 
a high temperature. 

The digestion of fats is mainly a process of emul- 
sion. With the intestinal fluids, the bile, especially, 
the fats form an emulsion in which the globules 
are finely divided, and rendered capable of passing 
through the membranes into the circulatory sys- 
tem. The change, if any, is not one destructive 
of the properties of the fatty matters. 

If we define cooking as the application of heat, The Digestion 
then whatever we do to fats in the line of cooking 
them is liable to hinder rather than help their diges- 



of Fat. 



46 COOKING AND CLEANING. 

tibility. The flavor which cooking gives to food 
materials containing fat is, in general, due not to 
any flavor of the fat but to substances produced 
in the surrounding tissues. 
hs'S'toii- ^ ats ma y ^ e heated to a temperature far above 

Fats ture ° n *^at of boiling water without showing any change ; 

but there comes a point, different for each fat, 
where reactions take place, the products of which 
irritate the mucous membranes and, therefore, in- 
terfere with digestion. It is the volatile products of 
such decomposition which cause the familiar action 
upon the eyes and throat during the process of 
frying, and, also, the tell-tale odors throughout the 
house. The indigestibility of fatty foods, or foods 
cooked in fat, is due to these harmful substances 
produced by the too high temperature. It must 
not be inferred from what has been said that the 
oxidation of starch and fat is the only source of 
heat in the animal body. A certain quantity is un- 
doubtedly derived from the chemical changes of 
the other portions of food, but the chemistry of 
these changes is not yet fully understood. 



CHAPTER IV. 

Nitrogenous Constituents. 

THE animal body is a living machine, capable 
of doing work — raising weights, pulling loads, 
and the like. The work of this kind which it does 
can be measured by the same standard as the work 
of any machine, i. e., by the mechanical unit of 
energy — the foot-ton. 

The power to do mechanical work comes from 
the consumption of fuel, — the burning of wood, 
coal or gas; and this potential energy of fuel is often 
expressed in units of heat or calories, a calorie being 
nearly the amount of heat required to raise two 
quarts of water one degree Fahrenheit. The ani- 
mal body also requires its fuel, namely food, in 
order to do other work — its thinking, its talking or 
even its worrying. 

The animal body is more than a machine. It 
requires fuel to enable it not only to zvork but also 
to live, even without working. About one-third of 
the food eaten goes to maintain its life, for while 
the inanimate machine is sent periodically to the 
repair-shop, the living machine must do its own 



Animal P>< dy 
a Machint. 



Calories. 



Need of Body 
Fuel. 



Waste-Re- 
pair. 



48 THE CHEMISTRY OF 

repairing, day by day, and minute by minute. 
Hence it is that the estimations of the fuel and re- 
pair material needed to keep the living animal body 
in good working and thinking condition are, in the 
present state of our knowledge, somewhat empir- 
ical; but it is believed that, within certain wide 
limits, useful calculations can be made by any one 
willing to give a little time and thought to the sub- 
ject. Our knowledge may be rapidly increased if 
such study is made in many localities and under 
varying circumstances. 

The adult animal lives, repairs waste, and does 
work; while the young animal does all these and 
more — it grows. For growth and work something 
else is needed beside starch and fat. The muscles 
are the instruments of motion, and they must grow 
and be nourished, in order that they may have 
power. The nourishment is carried to them by the 
blood in which, as well as in muscular tissue, there 
is found an element which we have not heretofore 
considered, namely, nitrogen. It has been proved 
that the wear and tear of the muscles and brain 
causes the liberation of nitrogenous compounds, 
which pass out of the system as such, and this loss 
must be supplied by the use of some kind of food 
which contains nitrogen. Starch and fat do not 
contain this element; therefore they cannot furnish 
it to the blood. 



COOKING AND CLEANING. 49 

Nitrogenous food-stuffs comprise at least two {££gX 
large groups, the Albumins or Proteids and the 
Albuminoids. 

Albumins. 

The Albumins in some form are never absent 
from animal and vegetable organisms. They are 
more abundant in animal flesh and in the blood. 
The typical food of this class is the white of egg, 
which is nearly pure albumin. Other common arti- 
cles of diet belonging to this group are the casein 
of milk, the musculin of animal flesh, the gluten of 
wheat, and the legumin of peas and beans. 

Egg albumin is soluble in cold water, but coagu- 
lates at about 160 degrees F. At this point it is 
tender, jelly-like, and easily digested, while at a 
higher temperature it becomes tough, hard and sol- 
uble with difficulty. 

The albumin of flesh is contained largely in the 
blood ; therefore the juices of meat extracted in cold 
water form an albuminous solution. If this be 
heated to the right temperature the albumin is 
coagulated and forms the "scum" which many a 
cook skims off and throws away. In doing this 
she wastes a large portion of the nutriment. She 
should retain this nutrition in the meat by the quick 
coagulation of the albumin of the exterior, which 
will prevent further loss, or use the nutritive solu- 



50 



THE CHEMISTRY OF 



Collagen. 



Cooking of 

Nitrogenous 

Food-Stuffs. 



tion in the form of soups or stews. "Clear soups" 
have lost much of their nutritive value and, there- 
fore, belong among the luxuries. 

Albuminoids. 

The animal skeleton — horns, bones, cartilage, 
connective tissue, etc., contain nitrogenous com- 
pounds which are converted by boiling into sub- 
stances that form with water a jelly-like mass. 
These are known as the gelatins. 

The chief constituent of the connective tissues is 
collagen. This is insoluble in cold water, but in hot 
water becomes soluble and yields gelatine. Colla- 
gen swells when heated and when treated with 
dilute acids. Steak increases in bulk when placed 
over the coals, and tough meat is rendered tender 
by soaking in vinegar. Freshly killed meat is tough, 
for the collagen is dry and hard. In time it becomes 
softened by the acid secretions brought about 
through bacterial action, and the meat becomes 
tender and easily masticated. Tannic acid has the 
opposite effect upon collagen, hardening and 
shrinking it. This effect is taken advantage of in 
tanning, and is the disadvantage of boiled tea as 
a beverage. 

Cooking should render nitrogenous food more 
soluble because here, as in every case, digestibility 
means solubility. Therefore, when the white of 



COOKING AND CLEANING. 61 

egg (albumin), the curd of milk (casein), or the glu- 
ten of wheat are hardened by heat, a much longer 
time is required to effect solution. 

As previously stated, egg albumin is tender and 
jelly-like when heated from 160 degrees to 180 de- 
grees. This fact should never be forgotten in the 
cooking of eggs. Raw eggs are easily digested 
and are rich in nutrition; when heated just enough 
to coagulate the albumin or "the white," their di- 
gestibility is not materially lessened; but when 
boiled the albumin is rendered more difficultly 
soluble. 

To secure the greatest digestibility in combina- 
tion with palatibility, they may be put into boiling 
water, placed where the temperature can be kept 
below 1 80 degrees, and left from ten to fifteen min- 
utes, or even longer, as the albumin will not harden 
and the yolk will become mealy. 

To fry eggs the fat must reach a temperature — 
300 degrees or over — far above that at which the 
albumin of the egg becomes tough, hard, and well- 
nigh insoluble. 

The oyster, though not rich in nutrition, is read- Oysters, 
ily digested when raw or slightly warmed. When 
fried in a batter, it is so protected by the water in 
the dough that the heat does not rise high enough 
to render insoluble the albuminous morsel within. 
Frying in crumbs (in which there is always 30 to 40 



52 THE CHEMISTRY OF 

per cent water, even though the bread be dry) is 
another though less efficient method of protection 
for the albumin. Corn meal, often used as a coat- 
ing, contains 10 to 12 per cent of water. 
Gluten - Experiments on the digestibility of gluten have 

proved that a high temperature largely decreases 
its solubility. Subjected to artificial digestion for 
the same length of time, nearly two and one half 
times as much nitrogen was dissolved from the raw 
gluten as from that which had been baked.* 

When gluten is combined with starch, as in the 
cereals, the difficulties of correct cooking are many, 
for the heat which increases the digestibility of the 
starch decreases that of the gluten. 
Casein. The same principle applies to casein — the albu- 

minous constituent of milk. There seems to be no 
doubt that boiling decreases its solubility, and, con- 
sequently, its digestibility for persons of delicate 
digestive power. 

The cooking of beans and all leguminous vege- 
tables should soften the cellulose and break up 
the compact grains of starch. Vegetables should 
never be cooked in hard water, for the legumin of 
the vegetable forms an insoluble compound with 
the lime or magnesia of the water. 

In the case of flesh the cooking should soften 

*The Effect of Heat upon the Digestibility of Gluten, by Ellen H. Richards. 
A. M., S. B., and Elizabeth Mason, A. B. Technology Quarterly, Vol. vii., 63 



Legumin. 



COOKim AND CLEANING. 63 

and loosen the connective tissue, so that the little 
bundles of fibre which contain the nutriment may 
fall apart easily when brought in contact with the 
teeth. Any process which toughens and hardens 
the meat should be avoided. 

Whenever it is desired to retain the juices within 
the meat or fish, it should be placed in boiling water 
that the albumin of the surface may be hardened 
and so prevent the escape of the albumin of the 
interior. The temperature should then be low- 
ered and kept between 160 and 180 degrees 
during the time needed for the complete break- 
ing down of the connective tissues. When 
the nutriment is to be used in broths, stews 
or soups, the meat should be placed in cold 
water, heated very slowly and the temperature 
not allowed to rise above 180 degrees until the 
extraction is complete. To dissolve the softened 
collagen, a temperature of 212 degrees is necessary 
for a short time. 

The object of all cooking is to make the food- object of 
stuffs more palatable or more digestible or both 
combined. 

In general, the starchy foods are rendered more 
digestible by cooking; the albuminous and fatty 
foods less digestible. 

The appetite of civilized man craves and custom 
encourages the putting together of raw materials 



Cooking. 



54 THE CHEMISTRY OF 

of such diverse chemical composition that the 
processes of cooking are also made complex. 

Bread — the staff of life — requires a high degree 
of heat to kill the plant-life, and long baking to 
prepare the starch for solution; while, by the same 
process, the gluten is made less soluble. 

Fats, alone, are easily digested, but in the ordi- 
nary method of frying, they not only become de- 
composed themselves, and, therefore, injurious; 
but they also prevent the necessary action of heat, 
or of the digestive ferments upon the starchy ma- 
terials with which the fats are mixed. 

Pastry. Pastry owes its harmful character to this inter- 

ference of fat with the proper solution of the starch. 
Good pastry requires the intimate mixture of flour 
with solid fat. The starch granules of the flour 
must absorb water, swell, and burst before they can 
be dissolved. The fat does not furnish enough 
water to accomplish this, and it so coats the starch 
granules as to prevent the sufficient absorption of 
water in mixing, or from the saliva during mas- 
tication. This coating of fat is not removed till 
late in the process of digestion. The same effect is 
produced by the combining of flour and fat in 
made gravies. 

Effect of The effect of cooking upon the solubility of the 

three important food-principals may be broadly 
stated thus : — 



Cooking. 



COOKING AND CLEANING. 65 

Starchy foods are made more soluble by long 
cooking at moderate temperatures or by heat 
high enough to dextrinize a portion of the starch, 
as in the brown crust of bread. 

Nitrogenous foods. The animal and vegetable 
albumins are made less soluble by heat; the animal 
albuminoids more soluble. 

Fats are readily absorbed in their natural condi- 
tion, but are decomposed at very high temperatures 
and their products become irritants. 



T 



CHAPTER V. 

The Art of Cooking. 

Flavors and Condiments. 

HE science as well as the art of cooking lies in 
the production of a subtle something which 
gives zest to the food and which, though infinites- 
imal in quantity, is of priceless value. It is the 
savory potage, the mint, anise and cummin, the 
tasteful morsel, the appetizing odor, which is, 
rightly, the pride of the cook's heart. 
Flavors. The most general term for this class of stimu- 

lating substances is, perhaps, flavor — the gout of 
the French, the Genuss-Mittel (enjoyment-giver) of 
the Germans. 

The development of this quality in food — taste, 
savor, relish, flavor or what not, which makes "the 
mouth water," depends, in every case, upon chem- 
ical changes more subtle than any others known 
to us. The change in the coffee berry by roasting 
is a familiar illustration. The heat of the fire causes 
the breaking up of a substance existing in the berry 
and the production of several new ones. If the 
heat is not sufficient, the right odor will not be 



COOKING AND CLEANING. 57 

given ; if it is too great, the aroma will be dissipated 
into the air or the compound will be destroyed. 

This is an excellent illustration of the narrow Nature of 

i-i 1- • 1 Flavors. 

margin along which success lies. It is also chem- 
ically typical of the largest number of flavors, 
which seem to be of the nature of oils, set free by 
the breaking up of the complex substances of which 
they form a part. Nature has prepared these essen- 
tial oils by the heat of the sun. They give the taste 
to green vegetables ; while in fruits they are present 
with certain acids, and both together cause the 
pleasure-giving and therapeutic effects for which 
fruit is noted. 

It is probable that the flavors of roasted corn, 
well-cooked oatmeal, toasted bread, also belong to 
this class. Broiled steak and roasted turkey are 
also illustrations, and with coffee show how easily 
the mark is overstepped — a few seconds too long, 
a very few degrees too hot, and the delicate morsel 
becomes an acrid, irritating mass. 

From this standpoint, cooking is an art as exact 
as the pharmacist's, and the person exercising it 
should receive as careful preparation; for these 
flavors, which are so highly prized, are. many of 
them the drugs and poisons of the apothecary and 
are to be used with as much care. This is an addi- 
tional reason for producing them by legitimate 
means from the food itself, and not by adding the 



58 



THE CHEMISTRY OF 



Chemistry of 
Flavors. 



Condiments 
and their 
Effect. 



crude materials in quantities relatively enormous to 
those of the food substances. 

The chemistry of cooking is therefore largely the 
chemistry of flavor-production — the application of 
heat to the food material in such a way as to bring 
about the right changes and only these. 

The flavors produced by cooking, correctly done, 
will be delicate and unobtrusive. Usually, except 
for broiled meats, a low heat applied for a long 
time, with the use of closed cooking vessels, de- 
velops the best flavors ; while quick cooking, which 
necessitates a high temperature, robs the fine prod- 
ucts of nature's laboratory of their choicest ele- 
ments. Present American cookery, especially, sins 
in this respect. Either the food is insipid from lack 
of flavor or crudely seasoned at the last moment. 

The secret of the success of our grandmothers' 
cooking lay not solely in the brick oven — in the 
low, steady heat it furnished — but in the care, 
thought, and infinite pains they put into the prep- 
aration of their simple foods. Compared with 
these, the "one-minute" cereals, the "lightning" 
pudding mixtures of the present are insipid, or 
tasteless. Experience with the Aladdin Oven is an 
education in flavor production. 

Another source of stimulating flavor is found in 
the addition of various substances called Condi- 
ments. These consist of materials, of whatever 



COOKING AND CLEANING. 59 

nature, added to the food compounds, to give them 
a relish. Their use is legitimate; their abuse, harm- 
ful. The effect of flavors is due to the stimulation 
of the nerves of taste and smell. Condiments should 
be used in a way to cause a like stimulation of the 
nerves. If they are added to food materials before 
or during the cooking process, a small quantity 
imparts a flavor to the entire mixture. If added to 
the cooked food, a larger quantity is used and the 
effect lasts, not only while the food is in contact 
with the nerves of the mouth, but also throughout 
the digestive tract, causing an irritation of the 
mucous membranes themselves. The tissues be- 
come weakened, and, in time, lose the power of 
normal action. 

Cayenne pepper directjy applied to the food, 
although sometimes a help, is oftener the cause in 
dyspepsia. Highly seasoned food tends to weaken 
the digestion in the end, by calling for more secre- 
tion than is needed and so tiring out, as it were, 
the glands. It is like the too frequent and violent 
application of the whip to a willing steed — by and 
by he learns to disregard it. Just enough to accom- 
plish the purpose is nature's economy. 

This economy is quick to recognize and be satis- 
fied with a food which is easily digested without im- 
pairing the functional powers of the digestive 
fluids. A child seldom shows a desire for condi- 



60 



THE CHEMISTRY OF 



ments unless these have been first unwisely added 
by adults. Flavors are largely odors, or odors and 
tastes combined, and act upon the nervous system 
in a natural way. Condiments, in many cases, are 
powerful, stimulating drugs, exciting the inner lin- 
ings of the stomach to an increased and abnormal 
activity. Medicinally they may act as tonics. The 
skill of the cook consists in steering between the 
two digestion possibilities — hinder and help. 

Some relish-giving substances, as meat extracts, 
the caffeine of coffee, theine of tea, theo-bromine of 
cocoa, and alcohol of wines go directly into the 
blood and here act upon the nervous system. They 
quicken the circulation and, therefore, stimulate to 
increased activity. The cup of coffee thus drives 
out the feeling of lassitude from wearied nerves and 
muscles. Wine should never be treated as an arti- 
cle of diet, but as a Gennss-Mittcl. 

The secret of the cooking of vegetables is the 
judicious production of flavor. In this the 
French cook excels. She adds a little meat juice to 
the cooked vegetables, thus obtaining the desired 
flavor with the cheaper nutritious food. This wise 
use of meats for flavor, while the actual food value 
is made up from the vegetable kingdom, is an im- 
portant item in public kitchens, institutions, or 
wherever expense must be closely calculated. 

In the study of economy, flavor-creation is of the 



COOKING AND CLEANING. 61 

utmost importance. In foods, as everywhere, 
science and art must supplement the purse, making 
the few and cheaper materials necessary for nutri- 
tion into a variety of savory dishes. Without the 
appetizing flavor, many a combination of food ma- 
terials is utterly worthless, for this alone stimu- 
lates the desire or appetite, the absence of which 
may prevent digestion. Food which pleases the 
palate, unless this has been abnormally educated, 
is usually wholesome, and judgment based on 
flavor is normally a sound one. 

- Starch may be cooked according to the most ap- Conditions 
proved methods; but, if there is no saliva, the starch 
is without food value. The piece of meat may be 
done to a turn; but, if there is no gastric juice in 
the stomach, it will not be dissolved, and hence is 
useless. A homely illustration will best serve 
our turn, — a cow may retain her milk by 
force of will. It is well known how much 
a contented mind has to do with her readi- 
ness to give milk and the quantity of 
milk she will yield. The various glands of the 
human body seem to have a like action. The dry 
mouth fails to moisten the food, and the stimulating 
flavor is lost. On the other hand the mouth 
"waters," and food is soon digested. The cow may 
be utterly foolish and whimsical in her ideas — so 
may persons. There may not be the least reason 



62 



THE CHEMISTRY OF 



Serving 



Discretion in 
Cooking. 



Bacterial 
Action Pro- 
duces 
Flavors. 



Cooking an 
Art. 



why a person should turn away from a given food, 
but if he does ? He suffers for his whims. 

Hence the cook's art is most important, for its 
results must often overcome adverse mental con- 
ditions by nerve-stimulating flavors. The art 
of serving, though out of place here, should be at- 
tentively studied with the effect on the appetite 
especially in view. This is of the utmost im- 
portance in connection with hospital cooking. 

Specific flavors, though agreeable in themselves, 
should be used with discretion. In Norway, the 
salmon is designedly cooked so as not to retain 
much of its characteristic savor, for this is too de- 
cided a flavor for an article of daily diet. In soups 
and stews a "bouquet" of flavors is better than the 
prominence of any one, although certain favorite 
dishes may have a constant flavor. 

Nature has produced many flavors and guarded 
well the secret of their production; but science is 
fast discovering their sources, as bacterial life and 
action are better understood. Now, the "June 
flavor" of butter may be produced in December, 
by inoculating milk with the right "butter 
bacillus." 

Cooking has thus become an art worthy the at- 
tention of intelligent and learned women. The 
laws of chemical action are founded upon the laws 
of definite proportions, and whatever is added more 



COOKING AND CLEANING. 63 

than enough, is in the way. The head of every 
household should study the condition of her fam- 
ily, and tempt them with dainty dishes, if that is 
what they need. Let her see to it that no burst of 
ill temper, no sullen disposition, no intemperance 
of any kind be caused by her ignorance or her dis- 
regard of the chemical laws governing the reactions 
of the food she furnishes. 

When this science and this art takes its place be- 
side the other sciences and other arts, one crying 
need of the world will be satisfied. 

We have now considered the three classes of 
food in one or more of which all staple articles of 
diet may be placed — the carbohydrates (starch and 
sugar), the fats and the nitrogenous material. Some 
general principles of diet, indicated by science, re- 
main to be discussed. 

Diet. 

All preparation of food-stuffs necessary to make ^estion °' 
them into suitable food for man comes under the Saliva, 
head of what has been called "external digestion." 
The processes of internal digestion begin in the 
mouth. Here the saliva not only lubricates the 
finely divided portions of the food materials, but, 
in the case of starch, begins the process of chang- 
ing the insoluble starch into a soluble sugar. This 
process is renewed in the small intestine. The fats 



64 



THE CHEMISTRY OF 



Mastication. 



Pepsin and 
Acid of 
Stomach. 



Decomposi- 
tion Products. 



are emulsified in the small intestine, and, with the 
soluble carbohydrates, are here largely absorbed. 

All the chemical changes which the nitrogenous 
food stuffs undergo are not well understood. Such 
food should be finely comminuted in the mouth, 
because, as before stated, chemical action is rapid 
in proportion to the fineness of division; but it is 
in the stomach that the first chemical change 
occurs. 

The chief agents of this change are pepsin 
and related substances, aided by the acid of the 
gastric juice; these together render the nitrogenous 
substance soluble and capable of passing through 
the membranes. Neither seems able to do this 
alone, for if the acid is neutralized, action ceases; 
and if pepsin is absent, digestion does not take 
place. 

Decompositions of a very complex kind occur, 
peptones are formed which are soluble compounds, 
and the nitrogen finally passes out of the system as 
urea, being separated by the kidneys, as carbon di- 
oxide is separated by the lungs. 

One of the most obvious questions is: Which is 
best for human food — starch or fat, beans and peas, 
or flesh? As to starch or fat, the question has been 
answered by experience, and science has only tried 
to explain the reason. The colder the climate, the 
more fat the people eat. The tropical nations live 



COOKING AND CLEANING. 



65 



chiefly on starchy foods, as rice. From previous 
statements it will be seen that this is right in princi- 
ple. Fat yields more heat than rice; therefore the 
inference is plain that in the cold of winter fat is 
appropriate food, while in the heat of summer rice 
or some other starchy food should be substituted. 

The diet of summer should also contain much 
fruit. Increased perspiration makes necessary an 
increased supply of water. This may be furnished 
largely by fruits, and with the water certain acids 
are taken which act as correctives in the digestive 
processes. 

No evident rule can be seen in the case of the 
albuminous foods. At most, the class can be di- 
vided into three groups. The first includes the ma- 
terial of vegetable origin, as peas, lentils, and the 
gluten of wheat. The second comprises the white 
of Qgg and the curd of milk — material of animal 
origin. The third takes in all the animal flesh used 
by mankind as food. 

Considering the question from a purely chemical 
standpoint, without regarding the moral or social 
aspects of the case, two views stand out clearly: 
ist. If the stored-up vegetable matter has required 
the force derived from the sun to prepare it, the 
tearing apart and giving back to the air and earth 
the elements of which it was built up will yield the 
same amount of force to whatever tears it down; 



Seasonable 
Diet. 



Economy of 
a Mixed 
Diet. 



66 THE CHEMISTRY OE 

but a certain amount of energy must be used up in 
this destruction. 2d. If the animal, having accom- 
plished the decomposition of the vegetable and ap- 
propriated the material, is killed, and the prepared 
nitrogenous food in the form of muscle is eaten by 
man, then little force is necessary to render the 
food assimilable ; it is only to be dissolved in order 
that it may enter into the circulation. The force- 
producing power is not lost; it is only transferred 
to another animal body. Hence the ox or the 
sheep can do a part of man's work for him in pre- 
paring the vegetable food for use, and man may 
thus accomplish more than he otherwise could. 
This digestion of material outside of the body is 
carried still further, by man, in the manufacture of 
partially digested foods, — "malted," "peptonized," 
"pre-digested," etc. Exclusive use of these is 
fraught with danger, for the organs of digestion 
lose power, if that which they have, however 
little, be long unused. 
Food of Nearly all, if not all, young animals live on food 

Animals. Q f animal origin. The young of the human race 

live on milk; but it has been found by experience 
that milk is not the best food for the adult to live 
upon to the exclusion of all else. It is not con- 
ducive to quickness of thought or general bodily 
activity. 
Sbfe°Food g " Experience leads to the conclusion that mankind 



COOKING AND CLEANING. 67 

needs some vegetable food. Two facts sustain this 
inference. The digestive organs of the herbivorous 
animals form fifteen to twenty per cent of 
the whole weight of the body. Those of 
the carnivorous animals form five to six 
per cent, those of the human race, about 
eight per cent. The length of the canal 
through which the food passes varies in about the 
same ratio in the three classes. A mixed diet seems 
to be indicated as desirable by every test which has 
been applied; but the proportions in which the 
vegetable and animal "food are to be mingled, as 
well as the relative quantities of carbonaceous and 
nitrogenous material which will give the best effi- 
ciency to the human machine are not so easily 
determined. 

Nature seems to have made provision for the ex- Wa tcr and 
cess of heat resulting from the oxidation of too 
much starch or fat, by the ready means of evapora- 
tion of water from the surface; this loss of water 
being supplied by drinking a fresh supply, which 
goes, without change, into the circulation. The 
greater the heat, the greater the evaporation ; hence 
the importance of water as an article of diet, espe- 
cially for children, must not be overlooked. For 
an active person, the supply has been estimated at 
three quarts per day. Water is the heat regulator 
of the animal body. An article entitled "Water 



Air as Food. 



68 THE CHEMISTRY OF 

and Air as Food,"* by one of the authors of this 
book, treats this subject more thoroughly. 

Dangers of While dangerous disease seldom results from 

eating an excess of starch or fat, because the por- 
tion not wanted is rejected as if it were so much 
sand, many of the most complicated disorders do 
result from an excess of nitrogenous diet. 

The readiness with which such substances under- 
go putrefaction, and the many noxious products to 
which such changes give rise, should lead us to be 
more careful as to the quantity of this food. 

From experiments made by the best investiga- 
tors, it seems probable that only one third of the 
estimated daily supply of food is available for ki- 
netic force ; that is, that only about one third of the 
total energy contained in the daily food can be util- 
ized in digging trenches, carrying bricks, climbing 
mountains, designing bridges, or writing poems 
and essays. The other two thirds is used up in the 
internal work of the body — the action of the heart, 
lungs, and the production of the large amount of 
heat necessary to life. 

Dietaries. It has been estimated that a growing person 

needs about one part of nitrogenous food to four of 
starch and fat; a grown person, one part nitro- 
genous to five or six of starch and fat. If this is 

♦Rumford Kitchen Leaflet, No. 6, American Kitchen Magazine, Vol. IV., 
357. 



COOKING AND CLEANING. 69 

true, then we may make out a life ration, or that 
amount of food which is necessary to keep the 
human machine in existence. 

For this climate, and for the habits of our people, 
we have estimated this life ration as approximately: 

Proteid. Fat. Carbohydrates. Calories. 

75 grams. 40 grams. 325 grams. 2,000. 

The amount of energy given out in the form of 
work cannot exceed the amount of energy taken in 
in the form of food; so this life ration is increased 
to make a maximum and minimum for a work 
ration. For professional or literary persons the 
following may be considered a sufficient maximum 
and minimum: 



Proteid. 


Fat. 


Carbohydrates. 


Calories. 


i«5 grams. 


125 grams. 


450 grams. 


3.5°o- 


no grams. 


90 grams. 


420 grams. 


3,000. 



For hard manual labor about one-third is to be 
added to the above rations. An examination of the 
actual dietaries of some of the very poor who eat 
just enough to live, without doing any work, 
shows that in twelve cases the average diet was : 

Proteid. Fat. Carbohydrates. Calories. 

31 grams. 81 grams. 272 grams. 2,257. 

For further information on these points see the 
list of works at the end of this book. 

The first office of the food, then, is to keep the offices ot 
human body in a high condition of health; the 
second, to enable it to exert force in doing the work 



Food. 



70 COOKING AND CLEANING. 

of the world; and a third, the value of which it is 
hardly possible to estimate, is to furnish an im- 
portant factor in the restoration of the body to nor- 
mal condition, when health is lost. In sickness, 
far more than in health, a knowledge of the right 
proportions of the essential food substances, and of 
the absolute quantity or food value given, is im- 
portant. How many a life has been lost because of 
a lack of this knowledge the world will never know. 



PART II 



THE CHEMISTRY OF CLEANING. 



CHAPTER I. 
Dust. 



MANY a housewife looks upon dust as her in- 
veterate enemy against whom incessant war- 
fare brings only visible defeat. Between the battles, 
let us study the enemy — the composition of his 
forces, his tactics, his ammunition, in order that 
we may find a vantage ground from which to direct 
our assault, or from which we may determine 
whether it is really an enemy which we are fighting. 

The Century dictionary defines dust as "Earth, Definition of 
or other matter in fine dry particles so attenuated 
that they can be raised and carried by the wind." 
This suggests that dust is no modern product of 
the universe. Indeed, its ancestry is hidden in 
those ages of mystery before man was. Who can 
say that it does not reach to that eternity which can 
be designated only by "In the beginning?" 



72 THE CHEMISTRY OP 

Necessity of Tyndall proved by delicate experiments that 

when all dust was removed from the track of a 
beam of light, there was darkness. So before the 
command "Let there be light," the dust-condition 
of light must have been present. Balloonists find 
that the higher they ascend the deeper the color of 
the sky. When at a distance of some miles, the 
sky is nearly black, there is so little dust to scatter 
the rays of light. If the stellar spaces are dustless, 
they must be black and, therefore, colorless. The 
moisture of the air collects about the dust-particles 
giving us clouds and, with them, all the glories of 
sunrise and sunset. Fogs, too, are considered to 
be masses of "water-dust," and ships far out at sea 
have had their sails colored by this dust, while sail- 
ing through banks of fog. Thinking, now, of the 
above definition, it may be said that the earth, in 
its final analysis, must be dust deposited during 
past ages; that to dust is due the light necessary 
to life, and that without it certain phenomena of 
nature — clouds, color, fog, perhaps, even rain and 
snow could not exist. 

It behooves us, then, as inhabitants of this dust- 
formed and dust-beautified earth to speak well of 
our habitation. We have found no enemy yet. 
The enemy must be lurking in the "other matter." 
This the dictionary says is in powdered form, car- 
ried by the air, and, therefore, at times existent in 



COOKING AND CLEANING. 



73 



it, as has been seen. A March wind gives sensible 
proof of this, but what about the quiet air, whether 
out of doors or in our houses? 

An old writer has said: "The sun discovers 
atonies, though they be invisible by candle-light, 
and makes them dance naked in his beams." Those 
sensible particles with these "atonies," which be- 
come visible in the track of a beam of light when- 
ever it enters a darkened room, make up the dust 
whose character is to be studied. 

Astronomers find meteoric dust in the atmos- 
phere. When this falls on the snow and ice fields 
of the Arctic regions, it is readily recognized. The 
eruption of Krakatoa proved that volcanic dust' is 
disseminated world-wide. Dust contains mineral 
matter, also, from the wear and tear of nature's 
forces upon the rocks, bits of dead matter given off 
by animal and vegetable organisms, minute fibres 
from clothing, the pollen of plants, the dry and pul- 
verized excrement of animals. These constituents 
are easily detected — are they all? 

Let a mixture of flour and water stand out-of- 
doors, leave a piece of bread or bit of cheese on 
the pantry shelves for a week. The mixture fer- 
ments, the bread and cheese mold. Formerly, these 
changes were attributed to the "access of air" — i. e., 
to the action upon the substances, of the oxygen of 
the air; later experiments have proved that if the 



Visible and 

Invisible 

Dust. 



Composition 
of Dust 



Dust Plants. 



74 THE' CHEMISTRY OF 

air be previously passed through a cotton-wool 
filter it will cause no change in the mixture. The 
oxygen is not filtered out, so it cannot be the cause 
of the fermentation. Now, such phenomena of 
fermentation are known to be caused by minute 
vegetable organisms which exist everywhere in the 
air and settle from it when it becomes dry and still. 
They are molds, yeasts and bacteria. All are mi- 
croscopic and many sub-microscopic.^ They are 
found wherever the atmosphere extends — some 
inches below the surface of the ground and 
some miles above it, although on the tops of the 
highest mountains and, perhaps, far out at sea, 
the air is practically free from earthly dust, 
and therefore nearly free from these forms. The 
volcanic dust of the upper air does not appear to 
contain them. They are all spoken of as "germs," 
because they are capable of developing into grow- 
ing forms. All are plants belonging to the fungi; 
in their manner of life essentially like the plants 
we cherish, requiring food, growing, and repro- 
ducing their kind. They require moisture in order 
to grow or multiply; but, like the seeds of higher 
plants, can take on a condition calculated to resist 
hard times and endure these for long periods ; then 
when moisture is furnished, they immediately 
spring into growth. In the bacteria these spores 
are a resting stage, not primarily reproduc- 



COOKING AND CLEANING. 



75 



tive; while, in molds, they bring forth an active, 
growing plant. 

The common puff-ball (Lycoperdon), the "smoke" 
ball of the country child, well illustrates both vege- 
tative and spore stages. This belongs to the fungi, 
is closely related to the molds, and consists of a 
spherical outer wall of two layers, enclosing tissues 
which form numerous chambers with membraneous 
partitions. Within these chambers are formed the 
reproductive cells or spores. When ripe, the mass 
becomes dry, the outer layer of the wall scales off, 
the inner layer splits open, allowing the minute dry 
spores to escape as a "cloud of dust." These are 
readily carried by the wind until caught on some 
moist spot favorable for their growth. They are 
found on dry, sandy soils, showing that very little 
moisture is needed; but when this is found, the 
spore swells, germinates, and grows into a new 
vegetative ball, which completes the cycle. 

Wheat grains taken from the wrappings of mum- 
mies are said to have sprouted when given moist- 
ure and warmth. Whether this be true or not, there 
can be no doubt that the vitality of some seeds and 
spores is wonderfully enduring. 

The spores of some of the bacteria may be boiled 
and many may be frozen — still life will remain. 

Aristotle declared that "all dry bodies become 
damp and all damp bodies which are dried engen- 



Spores. 



Vital Endur- 
ance. 



Dangerous 
Dust, 



76 THE CHEMISTRY OF 

der animal life." He believed these dust germs to 
be animalcules spontaneously generated wherever 
the conditions were favorable. How could he, with- 
out the microscope, explain in any other way the 
sudden appearance of such myriads of living forms? 

Now, it is recognized that the air everywhere 
contains the spores of molds and bacteria, and it 
is this dust, carried in the air, which falls in our 
houses. This is our enemy. 

A simple housemaid once said that the sun 
brought in the dust "atomes" through the window, 
and the careful, old, New England housewife 
thought the same. So, she shut up the best room, 
making it dark and, therefore, damp. Unwittingly, 
she furnished to them the most favorable conditions 
of growth, in which they might increase at the rate 
of many thousands in twenty-four hours. 

"Let there be light" must be the ever-repeated 
command, if we would take the first outpost of the 
enemy. 

We live in an invisible atmosphere of dust, we 
are constantly adding to this atmosphere by the 
processes of our own growth and waste, and, finally, 
we shall go the way of all the earth, contributing 
our bodies to the making of more dust. Thus dust 
has a decided two-fold aspect of friendliness and 
enmity. We have no wish to guard ourselves 
against friends; so, for the present purposes, the 



COOKING AND CLEANING. 77 

inimical action of dust, as affecting the life and 
health of man, alone need challenge our attention. 
The mineral dust, animal waste, or vegetable 
debris, however irritating to our membranes, or 
destructive of our clothing, are enemies of minor 
importance, compared with these myriads of living 
germs, which we feel not, hear not, see not, and 
know not until they have done their work. 

From a sanitary point of view, the most im- Bacteria, 
portant of the three living ingredients of dust is 
that called bacteria. They are the most numerous, 
the most widely distributed, and perhaps the small- 
est of all living things. Their natural home is the 
soil. Here they are held by moisture, and by the 
gelatinous character caused, in large part, by their 
own vital action. When the surface of the ground 
becomes dry, they are carried from it, by the wind, 
into the air. Rain and snow wash them down; 
running streams take them from the soil; so that, at 
all times, the natural waters contain immense num- 
bers of them. They are heavier than the air and 
settle from it in an hour or two, when it is dry and 
still. They are now quietly resting on this page 
which you are reading. They are on the floor, the 
tops of doors and windows, the picture frames, in 
every bit of ''fluff" which so adroitly eludes the 
broom — in fact, everywhere where dust can lodge. 

The second ingredient, in point of numbers, is Molds, 



78 THE CHEMISTRY OF 

the molds. They, too, are present in the air, both 
outside and inside of our houses; but being much 
lighter than the bacteria, they do not settle so 
quickly, and are much more readily carried into the 
air again, by a very slight breeze. 

Yeasts. The third, or wild yeasts, are not usually trouble- 

some in the air or in the dust of the house, where 
ordinary cleanliness rules. 

"Dirt." To the bacteriologist, then, everything is dirty 

unless the conditions for germ-growth have been 
removed, and the germs, once present, killed. 
All of this dirt cannot be said to be "matter in the 
wrong place," only when it is the wrong kind of 
matter in some particular place. The bacteria are 
Nature's scavengers. Every tree that falls in the 
forest — animal or vegetable matter of all kinds is 
immediately attacked by these ever-present, invisi- 
ble agents. By their life-processes, absorbing, se- 
creting, growing and reproducing, they silently 
convert such matter into various harmless sub- 
stances. They are faithful laborers, earning an 
honest living, taking their wages as they go. Their 
number and omnipresence show the great amount 
of work there must be for them to do. 

Then why should we enter the lists against such 
opponents? Because this germ-community is like 
any other typical community. 

The majority of the individuals are law-abiding, 



COOKING AND CLEANING. 79 

respectable citizens; yet in some dark corner a thief 
may hide, or a cut-throat steal in unawares. If 
this happens, property may be destroyed and life 
itself endangered. 

All of these forms destroy our property; 
but a certain few of the bacteria cause disease 
and death. In a very real sense, so soon as an or- 
ganism begins to live it begins to die ; but these are 
natural processes and do not attract attention so 
long as the balance between the two is preserved. 
When the vital force is lessened, by whatever cause, 
disease eventually shows itself. Methods for the 
cure of disease are as old as disease itself; but 
methods for the prevention of disease are of late 
birth. Here and there along the past, some minds, 
wiser than their age, have seen the possibilities of 
such prevention; but superstition and ignorance 
have long delayed the fruition of their hopes. 

"An ounce of prevention is worth a pound of Prevention of 
cure," though oft repeated has borne scanty fruit 
in) daily living. When the cause of smallpox, 
tuberculosis, diphtheria, typhoid fever, and other 
infectious diseases is known to be a living plant, 
which cannot live without food, it seems, at first 
sight, a simple matter to starve it out of existence. 
This has proved to be no simple nor easy task; so 
much the more is each person bound by the law 
of self-love and the greater law, 'Thou shalt love 



Disease. 



80 THE CHEMISTRY OF 

thy neighbor as thyself," to do his part toward 
driving these diseases from the world. 

Any one of these dust-germs is harmless so long 
as it cannot grow. Prevent their growth in the 
human body, and the diseased condition cannot 
occur. 

Prevention, then, is the watchword of modern 
sanitary science. 

It may be asked: How do the germs cause dis- 
ease ? 

Why do they not always cause disease? 

Numerous answers have been given during the 
short time the germ theory of infectious diseases 
has been studied. If we follow the history of this 
study, we may find, at least, a partial answer. 
Action of A person is "attacked" by smallpox, diphtheria, 

lockjaw, typhoid fever, or some kindred disease. 
Common speech recognizes in the use of the word 
"attacked" that an enemy from outside has begun, 
by force, a violent onset upon the person. This 
enemy — a particular bacterium or other germ, has 
entered the body in some way. There may have 
been contact with another person ill with the same 
disease. The germ may have entered through food 
on which it was resting, by water, or by dust as 
it touched the exposed flesh, where the skin was 
broken by a scratch or cut. It found in the blood 
or flesh the moisture and warmth necessary for its 



Bacteria. 



COOKING AND CLEANING. 81 

growth, and, probably, a supply of food at once de- 
sirable and bountiful. It began to feed, to grow, 
and to multiply rapidly, until the little one became 
a million. At this stage the patient knew he was 
ill. It was thought, at first, that the mere presence 
in the body of such enormous numbers caused the 
disease. 

Bacteria like the same kinds of food which we Food of 

Bacteria. 

like. Though they can and will live on starvation 
rations, they prefer a more luxurious diet. This 
fact led to the idea that they supplied their larder 
by stealing from the food supply of the invaded 
body; so that, while the uninvited and unwelcome 
guest dined luxuriously, the host sickened of starva- 
tion. This answer is now rejected. 

The food of the bacteria is not only similar in 
kind to our own food, but it must also undergo like 
processes of solution and absorption. 

Solution is brought about by the excretion of 
certain substances, similar in character and in ac- 
tion to the ferments secreted in the animal mouth, 
stomach and intestines. These excretions reduce 
the food materials to liquids, which are then ab- 
sorbed. 

The pathogenic or disease-producing germs are 
found to throw out during their processes of as- 
similation and growth, various substances which 
are poisons to the animal body, as are aconite and 



S2 



THE CHEMISTRY OF 



digitalis. These are absorbed and carried by the blood 
throughout the entire system. These poisons are 
called toxines. It is now believed that it is these 
bacterial products, the toxines or poisons, which 
are the immediate cause of the diseased condition. 

inoculation. Inoculation of some of the lower animals with 

the poisoned blood of a diseased person, in which 
blood no germ itself was present, has repeatedly 
produced the identical disease. It is far easier to 
keep such manufacturers out of the body than to 
"regulate" their manufactures after an entrance has 
been gained. 

These faint glimpses into the "Philosophy of 
Cleanness" lead to another question, namely: How 
shall we keep clean? 

The first requisite for cleanness is light — direct 
sunlight if possible. It not only reveals the visible 
dirt, but allies itself with us as an active agent 
towards the destruction of the invisible elements of 
uncleanness. That which costs little or nothing is 
seldom appreciated; so this all-abundant, freely- 

Suniight. given light is often shut out through man's greed 

or through mistaken economy. The country dwell- 
er surrounds his house with evergreens or shade 
trees, the city dweller is surrounded by high brick 
walls. Blinds, shades, or thick draperies shut out 
still more, and prevent the beneficent sunlight from 
acting its role of germ-prevention and germ-de- 



Requisites 
for Clean- 



COOKING AND CLEANING. 83 

struction. Bright-colored carpets and pale-faced 
children are the opposite results which follow. 
"Sunshine is the enemy of disease, which thrives in 
darkness and shadow." Consumption and scrofu- 
lous diseases are well-nigh inevitable, when blinds 
are tightly closed and trees surround the house, 
causing darkness, and, thereby, inviting dampness. 
As far as possible let the exterior of the house be 
bathed in sunlight. Then let it enter every nook and 
cranny. It will dry up the moisture, without which 
the tiny disease germs or other plants cannot grow; 
it will find and rout them by its chemical action. 
Its necessity and power in moral cleanness, who 
can measure? 

More plentiful than sunlight is air. We cannot Pure Air. 
shut it out entirely as we can light; but there is 
dirty air just as truly as dirty clothes and dirty 
water. The second requisite for cleanness, then, 
is pure air. 

Primitive conditions of human life required no primitive 
thought of the air supply, for man lived in the open ; Life. mons c 
but civilization brings the need of attention and 
care for details; improvements in some directions 
are balanced by disadvantages in others; luxuries 
crowd out necessities, and man pays the penalty 
for his disregard of Nature's laws. Sunlight, pure 
air and pure water are our common birthright, 
which we often bargain away for so-called com- 
forts. 



84 THE CHEMISTRY OP 

Sunlight is purity itself. Man cannot contam- 
inate it, but the air about him is what man makes it. 
Naturally, air is the great "disinfectant, antiseptic 
and purifier, and not to be compared for a moment 
with any of artificial contrivance," but under man's 
abuse it may become a death-dealing breath. 

Charlemagne said: "Right action is better than 
knowledge ; but to act right one must know right." 
Nature's supply of pure air is sufficient for all, but 
to have it always in its pure state requires knowl- 
edge and constant, intelligent action. 
Products oi The gaseous products of the combustion carried 

Combustion. . , . ,,.,., .. - 

on within our bodies; like products from our arti- 
ficial sources of heat and light — burning coal, gas 
and oil ; waste matters of life and manufactures car- 
ried into the air through fermentation and putre- 
faction — all these, with the innumerable sources of 
dust we have already found, load the air with im- 
purities. Some are quickly recognized by sight, 
smell or taste; but many, and these the more dan- 
gerous, are unrecognizable by any sense. They 
show their actions in our weakened, diseased and 
useless bodies. Dr. James Johnson says: "All 
the deaths resulting from fevers are but a drop in 
the ocean, when compared with the numbers who 
perish from bad air." 
Air Pollution. The per cent of pollution in the country is much 

smaller than in the city, where a crowded popula- 



COOKING AND CLEANING. 85 

tion and extensive manufactories are constantly 
pouring forth impure matters, but by rapidly mov- 
ing currents, even this large per cent is soon diluted 
and carried away. Would that the air in country 
houses, during both winter and summer, might 
show an equally small per cent! 

Air is a real substance. It can be weighed. It AiraSub- 
will expand, and may be compressed like other 
gases. It requires considerable force to move it, 
and this force varies with the temperature. When 
a bottle is full of air, no more can be poured in. 
Our houses are full of air all the time. No more 
can come in till some has gone out. In breathing, 
we use up a little, but it is immediately replaced 
by expired air, which is impure. * Were there no 
exits for this air, no pure air could enter, and we 
should soon die of slow suffocation. The better 
built the house the quicker the suffocation, unless 
special provision be made for a current of fresh air 
to push out the bad. Fortunately no house is air 
tight. Air will come in round doors and windows, 
but this is neither sufficient to drive out the bad 
nor to dilute it beyond harm. Therefore the air of 
all rooms must be often and completely changed, 
either by special systems of ventilation, or by in- 
telligent action in the opening of doors and win- 
dows. 

Sunlight and pure air are the silent but powerful Qeanness 



86 COOKING AND CLEANING. 

allies of the housewife in her daily struggle toward 
the ideal cleanness, i. e., sanitary cleanness, the 
cleanness of health. Without these allies she may 
spend her strength for naught, for the plant-life of 
the quiet, -dust-laden air will grow and multiply far 
beyond her powers of destruction. These dust- 
plants or micro-organisms grow rapidly in warm 
places where there is moisture. Collections of 
dust in cracks and corners, lodged in depressions 
of the surface, as in seams and carvings, or held 
by rough, absorbent materials as fabrics, at all 
times furnish the seed. All organic materials 
furnish soil or food. Therefore the half-dried 
milk-can, the partly cleaned dripping-pan, the 
dampened clothes in the laundry basket, the wet 
dishcloth and damp towel will soon become a 
flourishing dust-garden. 

A dust-garden suggests growth ; growth of 
dust means fermentation with its consequent 
chemical changes. Fermentation is a process of 
decomposition which may end in putrefaction. 
This means economic waste. 

Civilized man requires so many articles for his 
convenience and comfort that the problem of 
cleanness has grown to be most complex. 

But dry dust is not the only enemy. The 
mixture of dust with greasy, sugary or smoky 
deposits makes the struggle twofold. 



CHAPTER II. 
Dust Mixtures. 



Grease and Dust. 

THE various processes of housework give rise 
to many volatile substances. These, the vapors 
of water or fat, if not carried out of the house in 
their vaporous state will cool and settle upon all 
exposed surfaces, whether walls, furniture or fab- 
rics. This thin film entangles and holds the dust, 
clouding and soiling, with a layer more or less visi- 
ble, everything within the house. Imperfect ven- 
tilation allows additional deposits from fires and 
lights — the smoky products of incomplete com- 
bustion. 

Thorough ventilation is, then, a preventive meas- 
ure, which ensures a larger removal not only of the 
volatile matters, but also of the dust, with its possi- 
ble disease germs. 

Dust, alone, may be removed from most sur- 
faces with a damp or even with a dry cloth, or from 
fabrics by vigorous shaking or brushing; but, 
usually, the greasy or sugary deposits must first be 
broken up and, thus, the dust set free. This must be 
accomplished without harm to the material upon 



Sources of 
Dirt. 



Removal of 
Dust. 



88 



THE CHEMISTRY OF 



Processes of 
Cleaning. 



Grease-Oils. 



Alkali Metals. 



which the unclean deposit rests. Here is a broad 
field for the application of chemical knowledge. 

Cleaning, then, involves two processes: First, 
the greasy film must be broken up, that the en- 
tangled dust may be set free. Second, the dust 
must be removed by mechanical means. Disinfec- 
tion sometimes precedes these processes, in or- 
der that the dangerous dust-plants may be killed 
before removal. 

To understand the methods of dust removal, it 
is necessary to consider the chemical character of 
the grease and, also, that of the materials effectual 
in acting upon it. 

Grease or fats, called oils when liquid at ordinary 
temperature, are chemical compounds made of dif- 
ferent elements, but all containing an ingredient 
known to the chemist as a fatty acid. 

The chemist finds in nature certain elements 
which, with the fatty acids, form compounds en- 
tirely different in character from either of the orig- 
inal ingredients. These elements are called the 
alkali metals and the neutral compounds formed by 
theif union with the acid of the fat are familiarly 
known to the chemist as salts. 

The chemical group of "alkali metals" comprises 
six substances : Ammonium, Caesium, Lithium, Po- 
tassium, Rubidium and Sodium. Two of the six — 
Caesium and Rubidium — were discovered by means 



COOKING AND CLEANING. 89 

of the spectroscope, not many years ago, in the min- 
eral waters of Durckheim, and, probably, the total 
amount for sale of all the salts of these two metals 
could be carried in one's pocket. A third alkali 
metal — Lithium — occurs in several minerals, and 
its salts are of frequent use in the laboratory, but it 
is not sufficiently abundant to be of commercial 
importance. As regards the three remaining alkali 
metals, the hydrate of Ammonium (NH 4 )OH, is 
known as "Volatile Alkali," the hydrates of Po- 
tassium, KOH, and Sodium, NaOH, as "Caustic 
Alkalies." With these three alkalies and their 
compounds, and these alone, are we concerned 
in housekeeping. The volatile alkali, Ammonia, is 
now prepared in quantity and price such that every 
housekeeper may become acquainted with its use. 
It does not often occur in soaps, but it is valuable 
for use in all cleansing operations — the kitchen, 
the laundry, the bath, the washing of woolens, and 
in other cases where its property of evaporation, 
without leaving any residue to attack the fabric or 
to attract anything from the air, is invaluable. The 
most extensive household use of the alkalies is in 
the laundry, under which head they will be more 
specifically described. 

Some .of the fatty acids combine readily with s <> a P s - 
alkalies to form compounds which we call soaps. 
Others in contact with the alkalies form emulsions, 



90 



THE CHEMISTRY OF 



The Problem 
of Cleaning. 



Cleaning of 

Different 

Materials. 



" Finish " of 
Woods. 



so-called, in which the fatty globules are suspended, 
forming an opaque liquid. These emulsions are 
capable of being indefinitely diluted with clear 
water, and, by this means, the fatty globules are all 
carried away. Most of the fats are soluble in ben- 
zine, ether, chloroform, naphtha or alcohol. 

If the housekeeper's problem were the simple 
one of removing the grease alone, she would solve 
it by the free use of one of these solvents or by 
some of the strong alkalies. This is what the 
painter does when he is called to repaint or to re- 
finish; but the housewife wishes to preserve the 
finish or the fabric while she removes the dirt. She 
must, then, choose those materials which will dis- 
solve or unite with the grease without injury to the 
articles cleaned. 

The greasy film which entangles the unclean and 
possibly dangerous dust-germs and dust-particles 
is deposited on materials of widely different char- 
acter. These materials may be roughly divided 
into two classes : One, where, on account of some 
artificial preparation, the uncleanness does not 
penetrate the material but remains upon the sur- 
face, as on wood, metal, minerals, leather and some 
wall paper; the other, where the grease and dust 
settle among the fibres, as in fabrics. 

In the interior of the house, woods are seldom 
used in their natural state. The surface is covered 



COOKING AND CLEANING. 



91 



with two or more coatings of different substances 
which add to the wood durability or beauty. The 
finish used is governed by the character of the 
wood, the position and the purpose which it serves. 
The cleaning processes should affect the final coat 
of finish alone. 

Soft woods are finished with paint, stain, oil, 
shellac, varnish, or with two or more of these com- 
bined; hard woods with any of these and, in addi- 
tion, encaustics of wax, or wax with turpentine or 
oil. 

All these surfaces, except those finished with 
wax, may be cleaned with a weak solution of soap 
or ammonia, but the continued use of any such 
alkali will impair and finally remove the polish. 
Waxed surfaces are turned dark by water. Fin- 
ished surfaces should never be scoured nor cleaned 
with strong alkalies, like sal-soda or potash soaps* 
To avoid the disastrous effects of these alkalies the 
solvents of grease may be used or slight friction 
applied. Turpentine dissolves paint. 

Kerosene and turpentine are efficient solvents for 
grease and a few drops of these on a soft cloth may 
be used to clean all polished surfaces. The latter 
cleans the more perfectly and evaporates readily; 
the former is cheaper, safer, because its vapor is not 
so inflammable as that of turpentine, and it polishes 
a little while it cleans; but it evaporates so slowly 

* If the finish has become very greasy, smoky or worn, it may be 
economy to use as strong an alkali as sal-soda. The washing and rinsing 
should be as rapid as possible. Refinishing may be necessary for clean 
conditions. 



Varnish, Oil, 
Wax. 



Solvents of 
Grease. 



92 THE CHEMISTRY OF 

that the surface must be rubbed dry each time, or 
dust will be collected and retained. The harder the 
rubbing, the higher the polish.* 

Outside of the kitchen, the woodwork of the 
house seldom needs scrubbing. The greasy layer 
is readily dissolved by weak alkaline solutions, by 
kerosene or turpentine, while the imbedded dust is 
wiped away by the cloth. Polished surfaces keep 
clean longest. Strong alkalies will eat through the 
polish by dissolving the oil with which the best 
paints, stains or polishes are usually mixed. If the 
finish be removed or broken by deep scratches, the 
wood itself absorbs the grease and dust, and the 
stain may have to be scraped out. 

Woodwork, whether in floors, standing finish or 
furniture, from which the dust is carefully wiped 
every day, will not need frequent cleaning. A 
few drops of kerosene or some clear oil rubbed or 
with a second cloth will keep the polish bright and 
will protect the wood. 

Certain preparations of non-drying oils are now 
in the market, which, when applied to floors, serve 
to hold the dust and prevent its spreading through 
the room and settling upon the furnishings. They 
are useful in school-rooms, stores, etc., where the 
floor cannot be often cleaned. The dust and dirt 
stick in the oil and, in time, the whole must be 
cleaned off and a new coating applied. 

* Continued use of kerosene on white paint tends to turn it yellow. 



COOKING AND CLEANING. 93 

Many housewives fear to touch the piano, how- a ciean 
ever clouded or milky the surface may become. 
The manufacturers say that pianos should be 
washed with soap and water. Use tepid water with 
a good quality of hard soap and soft woolen or cot- 
ton-flannel cloths. Wash a small part at a time, 
rinse quickly with clear water that the soap may 
not remain long, and wipe dry immediately. Do 
all quickly. A well-oiled cloth wiped over the sur- 
face and hard rubbing with the hand or with cham- 
ois will improve the appearance. If there are deep 
scratches which go through the polish to the wood, 
first, cover them with oil and allow it to soak in, 
or dark lines will appear where the alkali and 
w r ater touched the natural wood. 

Painted surfaces, especially if white, may be paint, 
cleaned with whiting, applied with a moistened 
woolen cloth or soft sponge. Never let the 
cloth be wet enough for the water to run or 
stand in drops on the surface. Wipe "with 
the grain" of the wood, rinse in clear 
water with a second soft cloth and wipe 
dry with a third. All washed surfaces should 
be wiped dry, for moisture and warmth furnish the 
favorable conditions of growth for all dust-germs, 
whether bacteria or molds. Cheese cloth may be 
used for all polished surfaces, for it does not 
scratch and washes easily. 



94 THE CHEMISTRY OF 

Walls painted with oil paints may be cleaned 
with weak ammonia water or whiting in the same 
manner as woodwork; but if they are tinted with 
water colors, no cleaning can be done to them, for 
both liquids and friction will loosen the coloring 
matter. 

Waii-Paper. Papered walls should be wiped down with cheese 

cloth, with the rough side of cotton flannel, or some 
other soft cloth. This will effectually remove all 
free dust. Make a bag the width of the broom or 
brush used. Run in drawing strings. Draw the 
bag over the broom, and tie closely round the han- 
dle, just above the broom-corn. Wipe the walls 
down with a light stroke and the paper will not be 
injured. An occasional thorough cleansing will be 
needed to remove the greasy and smoky deposits. 
The use of bread dough or crumb is not recom- 
mended, for organic matter may be left upon the 
wall. A large piece of aerated rubber — the 
"sponge" rubber used by artists for erasing their 
drawings — may be used effectually, and will leave 
no harmful deposit. "Cartridge" paper may be 
scoured with fine emery or pumice powder, for the 
color goes through. Other papers have only a thin 
layer of color. 

Varnished and waxed papers are now made 
which may be wiped with a damp cloth. 

Leather. Leather may be wiped with a damp cloth or be 



COOKING AND CLEANING. 95 

kept fresh by the use of a little kerosene. An occa- 
sional dressing of some good oil, well rubbed in, 
will keep it soft and glossy. 

Marble may be scoured with fine sand-soap or Marble, 
powdered pumice, or covered with a paste of whit- 
ing, borax or pipe-clay, mixed with turpentine, 
ammonia, alcohol or soft soap. This should be left 
to dry. When brushed or washed off, the marble 
will be found clean. Polish with coarse flannel or 
a piece of an old felt hat. Marble is carbonate of 
lime, and any acid, even fruit juices, will unite 
with the lime, driving out the carbon dioxide, 
which shows itself in effervescence, if the quantity 
of acid be sufficient. Acids, then, should not touch 
marble, if it is desired to keep the polish intact. 
An encaustic of wax and turpentine is sometimes 
applied to marbles to give them a smooth, shining 
surface. These must not be scoured.* 

Pastes of whiting, pipe-clay, starch or whitewash 
may be put over ornaments of alabaster, plaster and 
the like. The paste absorbs the grease and, by rea- 
son of its adhesive character, removes the grime 
and dust. 

Most metals may be washed without harm in a Metals, 
hot alkaline solution or wiped with a little kerosene. 
Stoves and iron sinks may be scoured with the 
coarser materials like ashes, emery or pumice; but 
copper, polished steel, or the soft metals, tin, silver, 
and zinc require a fine powder that they may not 

*New marbles bave a very high polish which is easily scratched. 
These should be washed, not scoured. 



96 THE CHEMISTRY OF 

be scratched or worn away too rapidly. MetaJ 
bathtubs may be kept clean and bright with whiting 
and ammonia, if rinsed with boiling hot water and 
wiped dry with soft flannel or chamois. 

Porcelain. Porcelain or soapstone may be washed like metal 

or scoured with any fine material. 

Glass. Glass of windows, pictures and mirrors may be 

cleaned in many ways. It may be covered with a 
whiting paste mixed with water, ammonia or alco- 
hol. Let the paste remain till dry, when it may be 
rubbed off with a sponge, woolen cloth or paper. 
Polish the glass by hard rubbing with news- 
papers or chamois. Alcohol evaporates more 
quickly than water and therefore hastens the 
process; but it is expensive and should not touch 
the sashes, as it might turn the varnish. Very good 
results are obtained with a tablespoonful of kero- 
sene to a quart of warm water. In winter, when 
water would freeze, windows may be wiped with 
clear kerosene and rubbed dry. Kerosene does not 
remove fly specks readily, but will take off grease 
and dust. Fly specks may be dissolved in alcohol 
or strong alkali, or be scraped off with some 
dull, hard edge, as a cent, nickel or the back of 
a knife. 

Success in washing glass depends more upon 
manipulation than materials. It is largely a matter 
of patience and polishing. The outer surface of 



COOKING AND CLEANING. M 

windows often becomes roughened by the dissolv- 
ing action of rain water, or milky and opaque by 
action between the sun, rain and the potash or soda 
in the glass. Ordinary cleaning will not make such 
windows clear and bright. The opaqueness may 
sometimes be removed by rubbing with vinegar 
or dilute muriatic acid. Polish with whiting. 

Household fabrics, whether carpets, draperies Fabrics, 
or clothing, collect large quantities of dust, which 
no amount of brushing or shaking will entirely dis- 
lodge. They also absorb vapors which con- 
dense and hold the dust-germs still more firmly 
among the fibres. Here the fastness of color and 
strength of fibre must be considered, for a certain 
amount of soaking will be necessary in order that 
the cleansing material may penetrate through the 
fabric. In general, all fabrics should be washed 
often in an alkaline solution. If the colors will not 
stand the application of water, they may be cleansed 
in naphtha or rubbed with absorbents. The chem- 
istry of dyeing has made such progress during the 
last ten years that fast colors are more frequently 
found, even in the cheaper grades of fabrics, than 
could be possible before this time. It is now more 
a question of weak fibre than of fleeting color. 
Heavy fabrics may therefore be allowed to soak 
for some time in many waters, or portions of naph- 
tha, being rinsed carefully up and down without 



THE CHEMISTRY OF 



Inflammable 
Materials. 



Prevention of 
Dirt. 



rubbing. All draperies or woolen materials should 
be carefully beaten and brushed before any other 
cleaning is attempted. Wool fabrics hold much of 
the dirt upon their hook-like projections, and these 
become knotted and twisted by hard rubbing. If 
the fabric be too weak to be lifted up and down in 
the liquid bath, it may be laid on a sheet, over a 
folded blanket, and sponged on both sides with the 
soap or ammonia solution or with the naphtha. If 
the colors are changed a little by the alkalies, rinse 
the fabrics in vinegar or dilute acetic acid ; if affect- 
ed by acids, rinse in ammonia water. 

In the use of naphtha, benzine, turpentine, etc., 
great caution is necessary. The vapor of all these 
substances is extremely inflammable. They should 
never be used where there is any fire or light pres- 
ent, nor likely to be for several hours. A bottle 
containing one of them should never be left un- 
corked. Whenever possible, use them out-of- 
doors. 

With both dust and grease, prevention is easier 
than removal. If the oily vapors of cooking and 
the volatile products of combustion be removed 
from the kitchen and cellar, and not allowed to dis- 
sipate themselves throughout the house, the greasy 
or smoky deposits will be prevented and the re- 
moval of the dust-particles and dust-plants will be- 
come a more mechanical process. Such vapors 



COOKING AND CLEANING. 99 

should be removed by special ventilators or by win- 
dows open at the top, before they become con- 
densed and thus deposited upon everything in the 
house. Let in pure air, drive out the impure; fill 
the house with sunshine that it may be dry, and the 
problem of cleanness is largely solved. 

Economy of time, labor and materials results 
in removing dust and dust mixtures, frequently. 

"One keep-clean is worth a dozen make- 
clean" is as true now as it was generations ago. 
The sooner a wrong condition can be removed 
the easier will be its removal; less time will be 
required; and much less harm done to the 
articles cleaned. 

The organic matter which is present in most 
dirt tends to harden or to change in other ways 
and, therefore, to become removable with diffi- 
culty. It may undergo chemical changes which 
make it indelible. 

In fabrics the fibres may even be destroyed. 



T 



CHAPTER III. 
Stains, Spots, Tarnish. 

l HESE three classes include the particular de- 
posits resulting from accident, careless- 
ness, or the action of special agents, as the 
tarnish on metals. They are numerous in char- 
acter, occur on all kinds of materials and their re- 
moval is a problem which perplexes all women 
and which requires considerable knowledge and 
much patience to solve. A few suggestions may 
help some one who has not yet found the best 
way for herself. 

Grcascspots. Grease seems to be the most common cause of 

such spots. Small articles that can be laundered 
regularly with soap and water, give little trouble. 
These will be discussed in the following chapter. 

Absorbents of Spots of grease on carpets, heavy materials, or 

colored fabrics of any kind which cannot be con- 
veniently laundered, may be treated with absorb- 
ents. Heat will assist in the process by melting 
the grease. Fresh grease spots on such fabrics 
may often be removed most quickly by placing 
over the spot a piece of clean white blotting paper 
or butcher's wrapping paper, and pressing the spot 
with a warm iron. It is well to have absorbent 



COOKING AND CLEANING. 101 

paper or old cloth under the spot as well. Heat 
sometimes changes certain blues, greens and reds, 
so it is well to work cautiously and hold the iron 
a little above the goods till the effect can be noted. 

French chalk, — a variety of talc, or magnesia, 
may be scraped upon the spot and allowed to re- 
main for some time, or applied in fresh portions, 
repeatedly. If water can be used, chalk, fuller's 
earth or magnesia may be made into a paste with 
it or with benzine and this spread over the spot. 
When dry, brush the powder off with a soft brush. 

For a fresh spot on fabrics of delicate texture or 
color, when blotting paper is not at hand, a 
visiting or other card may be split and 
the rough inner surface rubbed gently over the 
spot. Slight heat under the spot may hasten the 
absorption. Powdered soapstone, pumice, whit- 
ing, buckwheat flour, bran or any kind of coarse 
meal are good absorbents to use on carpets or up- 
holstery. They should be applied as soon as the 
grease is spilled. Old spots will require a solvent 
and fresh ones may be treated in the same way. 

Grease, as has been said, may be removed in Solvents of 
three ways, by forming a solution, an emulsion, 
or a true soap. Wherever hot water and soap can 
be applied, the process is one of simple emulsion, 
and continued applications should remove both 
the grease and the entangled dust; but strong 



Grease. 



102 THE CHEMISTRY OF 

soaps ruin some colors and textures. Ammonia 
or borax may replace the soap, still the water may 
affect the fabric, so the solvents of grease are safer 
for use. Chloroform, ether, alcohol, turpentine, 
benzine and naphtha, all dissolve grease. In their 
commercial state some of these often contain im- 
purities which leave a residue, forming a dark ring, 
which is as objectionable as the original grease. 
Turpentine is useful for coarser fabrics, while 
chloroform, benzine and naphtha are best for silks 
and woolens. Ether or chloroform can usually 
be applied to all silks, however delicate. 
Whenever these solvents are used, there 
should be placed under the spot some absorb- 
ent material, like a thick pad of cloth, blot- 
ting paper or a layer of chalk to take up the 
excess of liquid. 

Then rub the spot from the outside toward 
the center to prevent the spreading of the 
liquid, to thin the edges, and, thus, to ensure 
rapid and complete evaporation. The cleansing 
liquid should not be left to dry of itself. 
The cloth should be rubbed dry, but very 
carefully, for the rubbing may remove the 
nap from woolen goods and, therefore, change 
the color or appearance. Apply the solvent 
with a cloth as nearly like the fabric to be 
cleaned, in color and texture, as possible, 



COOKING AND CLEANING. 



103 



or, in general, use a piece of sateen, which does 
not grow linty. On thick goods a stiff brush, 
and on thin goods a soft one, will reach into the 
meshes. This should be struck against the cloth 
more than rubbed across it. It is well to apply 
all cleansing liquids and all rubbing on the wrong 
side of the fabric. None of these solvents can be 
used near a flame. 

The troublesome "dust spot" has usually a neg- 
lected grease spot for its foundation. After the 
grease is dissolved, the dust must be cleaned out 
by thorough rinsing with fresh liquid or by brush- 
ing after the spot is dry. 

Our grandmothers found ox-gall an efficient 
cleanser both for the general and special deposits. 
It is as effectual now as then and is especially good 
for carpets or heavy cloths. It may be used clear 
for spots, or in solution for general cleansing and 
brightening of colors. Its continued use for car- 
pets does not fade the colors as ammonia or salt 
and water is apt to do. 

Cold or warm grease on finished wood can be 
wiped off easily with a woolen cloth moistened 
in soapsuds or with a few drops of turpentine. 
Soap should never be rubbed on the cloth except, 
possibly, for very bad spots round the kitchen 
stove or table. Solutions of washing soda, potash, 
or the friction, that may be used safely on linfin- 



" Dust 
spots." 



Ox-gall. 



Grease-spots 
on Wood. 



104 THE CHEMISTRY OF 

ished woods, will take out the grease but will also 
destroy the polish. 

Hot grease usually destroys the polish and 
sinks into the wood. It then needs to be treated 
like grease on unfinished wood or scraped out 
with fine steel wool or wire fibre, sandpaper or 
emery paper. The color and polish must then be 
renewed. When hot grease is spilled on wood or 
stone, if absorbents are not at hand, dash cold 
water on it immediately. This will solidify the 
grease and prevent its sinking deeply into the ma- 
terial. 

Grease or oil stains on painted walls, wall-paper 
or leather, may be covered with a paste of pipe- 
clay, or French chalk and water. Let the paste 
dry and after some hours carefully brush off the 
powder. Sometimes a piece of blotting paper laid 
over the spot and a warm iron held against this, 
will draw out the grease. These pastes of absorb- 
ent materials are good for spots on marbles. They 
may then be mixed with turpentine or ammonia 
or soft soap. 

Paint is made of oil, lead or zinc oxide 
arid pigment. Spots of paint, then, must be 
treated with something which will take out the oil, 
leaving the insoluble coloring matter to be 
brushed off. When fresh, such spots may 
be treated with turpentine, benzine or naph- 



COOKING AND CLEANING. 105 

tha. For delicate colors or textures, chloroform 
or naphtha is the safest. The turpentine, un- 
less pure, may leave a resinous deposit. This 
may be dissolved in chloroform or benzine, but 
care should be exercised in the use of alcohol 
for it dissolves some coloring matters. Old paint 
spots often need to be softened by the application 
of grease or oil; then the old and the new may be 
removed together. Whenever practicable, let all 
spots soak a little, that the necessity of hard rub- 
bing may be lessened. 

Paint on stone, bricks or marble, may be treated 
with strong alkalies and scoured with pumice 
stone or fine sand. 

Varnish and pitch are treated with the same varnish and 

. r Pitch. 

solvents as paint — turpentine being the one in 
general use, — when the article stained will not 
bear strong alkalies. Pitch and tar usually need 
to be covered first with grease or oil, to soften 
them. 

Wax spots made from candles should be re- Wax. 
moved by scraping off as much as possible, then 
treating the remainder with kerosene, benzine, 
ether, naphtha, or with blotting paper and a warm 
iron, as grease spots are treated. The soap and 
water of ordinary washing will remove slight 
spots. The spermaceti is often mixed with tallow 
which makes a grease spot, and with coloring mat- 
ters which may require alcohol, 



106 



THE CHEMISTRY OF 



Food Stains. 



Wheel 
G ease. 



Spots made by food substances are greasy, sug- 
ary or acid in their character, or a combination of 
these. That which takes out the grease will gen- 
erally remove the substance united with it, as the 
blood in meat juices. The sugary deposits are us- 
ually soluble in warm water. If the acids from 
fresh fruits or fruit sauces affect the color of the 
fabric, a little ammonia water may neutralize the 
acid and bring back the color. Dilute alcohol 
may sometimes be used as a solvent for colored 
stains from fruit. Blood requires cold or tepid 
water, never hot. After the red color is removed 
soap and warm water may be used. 

Blood stains on thick cloths may be absorbed 
by repeated applications of moist starch. 

Wheel-grease and lubricants of like nature are 
mixtures of various oils and may contain soaps or 
graphite. The ordinary solvents of the vegetable 
or animal oils will remove these mixtures from 
colored fabrics by dissolving the oil. The undis- 
solved coloring matter will, for the most part, pass 
through the fabric and may be collected on thick 
cloth or absorbent paper, which should always be 
placed underneath. From wash goods, it may be 
removed, readily, by strong alkalies and water, es- 
pecially if softened first by kerosene or the addition 
of more grease, which increases the quantity of 
soap made. Graphite is the most difficult of re- 
moval. 



COOKING AND CLEANING. 107 

Ink spots are perhaps the worst that can be en- ink stains, 
countered, because of the great uncertainty of the 
composition of the inks of the present day. When 
the character of an enemy is known it is a compar- 
atively simple matter to choose the weapons to be 
used against him, but an unknown enemy must be 
experimented upon, and conquest is uncertain. 
Methods adapted to the household are difficult to 
find, as the effective chemicals need to be applied 
with considerable knowledge of proportions and 
effects. Such chemicals are often poisons and, 
in general, their use by unskilled hands is not to 
be recommended. 

Fresh ink will sometimes yield to clear cold 01 
tepid water. Skimmed milk is safe and often ef- 
fective. If the cloth is left in till the milk sours, 
the result is at times more satisfactory. This has 
proved effective on light colored dress goods 
where strong acids might have affected the colored 
printed patterns. Some articles may have a bit of 
ice laid over the stain with blotting paper under 
it to absorb the ink solution. Remove the satur- 
ated portions quickly and continue the process till 
the stain has nearly or quite disappeared. The last 
slight stain may be taken out with soap and water. 
Some colored dress goods will bear the applica- 
tion of hot tartaric acid or of muriatic acid, a drop 
at a time, as on white goods. 



108 THE CHEMISTRY OF ' 

Ink on carpets, table covers, draperies or heavy, 
dark cloths of any kind, may be treated immedi- 
ately with absorbents to keep the ink from spread- 
ing. Bits of torn blotting paper may be held at 
the surface of the spot to draw away the ink on 
their hairy fibres. Cotton-batting acts in the same 
way. Meal, flour, starch, sawdust, baking soda 
or other absorbents may be thrown upon the ink 
and carefully brushed up when saturated. If much 
is spilled, it may be dipped up with a spoon or 
knife, adding a little water to replace that taken 
up, until the whole is washed out. Then dry the 
spot with blotting paper. The cut surface of a 
lemon may be used, taking away the stained por- 
tion as soon as blackened. Usually it requires 
hard rubbing to remove the last of the stain. Car- 
pets may be rubbed with a floor brush, while a 
soft toothbrush may be used for more delicate ar- 
ticles. With white goods a solution of bleaching 
powder may be used, but there is always danger 
of rotting the fibres unless rinsing in ammonia 
water follow, in order that the strong acid of the 
powder may be neutralized. 

Fresh ink stains on polished woods may be 
wiped off with clear water, and old stains of some 
inks likewise yield to water alone. The black col- 
oring matter of other inks may be wiped off with 
the water, but a greenish stain may still remain 



COOKING AND CLEANING. 



109 



which requires turpentine. In general, turpentine 
is the most effectual remover of ink from polished 
woods. 

The indelible inks formerly owed their perman- 
ence to silver nitrate; now, many are made from 
aniline solutions and are scarcely affected by any 
chemicals. The silver nitrate inks, even after ex- 
posure to light and the heat of the sun or of a hot 
flat-iron, may be removed by bleaching liquor. 
The chlorine replaces the nitric acid forming a 
white silver chloride. This may be dissolved in 
strong ammonia or a solution of sodium hyposul- 
phite. Sodium hyposulphite, which may be 
bought of the druggists, will usually remove the 
silver inks without the use of bleaching fluid and is 
not so harmful to the fibres. Some inks contain 
carbon which is not affected by any chemicals. 

The aniline inks, if treated with chemicals may 
spread over the fabric and the last state be worse 
than the first. Other chemicals are effective with 
certain inks, but some are poisonous in themselves 
or in their products, some injure the fabric, and 
all require a knowledge of chemical reactions in 
order to be safely handled. Dried ink stains on 
silver, as the silver tops of inkstands may be 
moistened with chloride of lime and rubbed hard. 

Polished marble may be treated with turpen- 
tine, "cooking soda" or strong alkalies, remerrh 



Indelible 
Inks. 



Aniline Inks 



Marble, 



110 THE CHEMISTRY OF 

bering that acids should never touch marble if it 
is desired to retain the polish. If the stain has 
penetrated through the polish, a paste of the alkali 
and turpentine may be left upon the spot for some 
time and then washed off with clear water. 

Porcelain. Sometimes the porcelain linings of hoppers 

and bowls become discolored with yellowish- 
brown stains from the large quantities of iron in 
the water supply. These should be taken off with 
muriatic acid. Rinse in clean water and, lastly, 
with a solution of potash or soda to prevent any 
injurious action of the acid on the waste pipes. 

Alcohol. Alcohol dissolves shellac. Most of the interior 

woodwork of the house, whether finish or furni- 
ture, has been coated with shellac in the process 
of polishing. If then, any liquid containing alco- 
hol, as camphor, perfumes, or medicines, be spilled 
upon such woodwork and allowed to remain, a 
white spot will be made, or if rubbed while wet, 
the dissolved shellac will be taken off and the bare 
wood exposed. 

Heat. Heat also turns varnish and shellac white. A 

hot dish on the polished table leaves its mark. 
These white spots should be rubbed with oil till the 
color is restored. 

If a little alcohol be brushed over the spot with 
a feather, a little of the surrounding shellac is dis- 
solved and spread over the stained spot. Hard 



COOKING AND CLEANING. 



Ill 



rubbing with kerosene will, usually, remove the 
spot and renew the polish. If the shellac be re- 
moved and the wood exposed the process of re- 
newal must be the original one of coloring, shellac- 
ing and polishing, until the necessary polish is ob- 
tained. 

Caustic alkalies, strong solutions of sal-soda, 
potash and the like, will eat off the finish. Apply 
sweet, olive, or other vegetable oils, in case of 
such accidents. The continued use of oils or al- 
kalies always darkens natural woods. 

The special deposits on metals are caused by the 
oxygen and moisture of the air, by the presence of 
other gases in the house, or by acids or corroding 
liquids. Such deposits come under the general 
head of tarnish. 

The metals, or their compounds, in common use 
are silver, copper and brass, iron and steel, tin, 
zinc and nickel. Aluminum is rapidly taking a 
"prominent place in the manufacture of household 
utensils. 

There is little trouble with the general greasy 
film or with the special deposits on articles in daily 
use, if they are washed in hot water and soap, 
rinsed well and wiped dry each time. Yet certain 
articles of food act upon the metal of tableware 
and cooking utensils, forming true chemical salts. 
The salts of silver are usually dark colored and in- 



A'.kalies. 



Chemical 
Compounds. 



Tarnish on 
Silver. 



112 THE CHEMISTRY OF 

soluble in water or in any alkaline liquid which will 
not also dissolve the silver. Whether found in the 
products of combustion, in food, as eggs, in the 
paper or cloth used for wrapping, in the rubber 
band of a fruit jar, or the rubber elastic which may 
be near the silver, sulphur forms with silver a gray- 
ish black compound — a sulphide of silver. All the 
silver sulphides are insoluble in water. Rub such 
tarnished articles, before washing, with common 
salt. By replacement, silver chloride, a white chem- 
ical salt, is formed, which is soluble in ammonia. 
If the article be not washed in ammonia it will soon 
turn dark again. Most of these metallic com- 
pounds formed on household utensils being insolu- 
ble, friction must be resorted to. 
silverware. The matron of fifty years ago took care of her 

silver herself or closely superintended its clean- 
ing, for the articles were either precious heirlooms 
or the valued gifts of friends. The silver of which 
they were made was hardened by a certain propor- 
tion of copper and took a polish of great brilliancy 
and permanence. The matron of to-day, who has 
the same kind of silver or who takes the same care, 
is the exception. Plated ware is found in most 
households. The silver deposited from the battery 
is only a thin coating of the pure soft metal — very 
bright when new, but easily scratched, easily tar- 
nished, and never again capable of taking a beauti- 



Powders 



COOKING AND CLEANING. 113 

ful polish. The utensils, being of comparatively 
little value, are left to the table-girl to clean. She, 
naturally, uses the material which will save her 
labor. 

In order to ascertain if there was any foundation silver 
for the prevalent opinion that there was mercury or 
some equally dangerous chemical in the silver pow- 
ders commonly sold, samples were purchased in 
Boston and vicinity, and in New York and vicinity. 

Of the thirty-eight different kinds examined. 

25 were dry powder. 
10 " partly liquid. 
3 " soaps. 

Of the twenty-five powders, fifteen were chalk or 
precipitated calcium carbonate, with a little color- 
ing matter, usually rouge. 

6 were diatomaceous earth. 
2 " fine sand entirely. 
2 " fine sand partly. 

Mercury was found in none. No other injurious 
chemical was found in any save the "electro-plating 
battery in a bottle," which contained potassium 
cyanide, KCN, a deadly poison; but it was labeled 
poison, although the label also stated that "all salts 
of silver are poison when taken internally." This 
preparation does contain silver, and does deposit a 
thin coating, but it is not a safe article for use. 



114 



THE CHEMISTRY OF 



Silver 
Polishes. 



Whiting. 



Cleaning of 
Silver in 
Quantity. 



Of the nine polishes, partly liquid, five contained 
alcohol and ammonia for the liquid portion; four, 
alcohol and sassafras extract. The solid portion, in 
all cases, was chalk, with, in one case, the addition 
of a little jeweler's rouge. 

The caution to be observed in the use of these 
preparations is in regard to the fineness of the ma- 
terial. A few coarse grains will scratch the coat- 
ing of soft silver. Precipitated chalk, CaC0 3 , or 
well-washed diatomaceous earth, Si0 2 , seem to be 
of the most uniform fineness. 

We may learn a lesson in this, as well as in many 
other things, from the old-fashioned housewife. 
She bought a pound of whiting for twelve cents, 
sifted it through fine cloth, or floated off the finer 
portion, and obtained twelve ounces of the same 
material, for three ounces of which the modern 
matron pays twenty-five or fifty cents, according to 
the name on the box. 

The whiting may be made into a paste with am- 
monia or alcohol, the article coated with this and 
left till the liquid has evaporated. Then the pow- 
der should be rubbed off with soft tissue paper or 
soft unbleached cloth, and polished with chamois. 

Sometimes it is desirable to clean a large quantity 
of silverware at one time, but the labor of scouring 
and polishing each piece is considerable. They 
may all be placed carefully in a large kettle — a clean 



COOKING AND CLEANING. 



115 



wash-boiler is convenient for packing the large 
pieces — and covered wi|th a strong solution of 
washing-soda, potash or borax. Boil them in this 
for an hour or less. Let them stand in the liquor 
till it is cold; then polish each piece with a little 
whiting and chamois. A good-sized piece of zinc 
boiled with the silverware will help to clean away 
any sulphides present, by replacing the silver in 
them and forming a white compound. 

Silver should never be rubbed with nor wrapped 
in woolen, flannel or bleached cloth of any kind, 
for sulphur is commonly used in bleaching proc- 
esses; nor should rubber in any form be present 
where silver is kept. The unused silver may be 
wrapped in soft, blue-white or pink tissue paper, 
prepared without sulphur, and packed in un- 
bleached cotton flannel cases, each piece separately. 
Silver jewelry, where strong soap or other alkali 
is not sufficient for the cleaning process, may be 
immersed in a paste of whiting and ammonia, and 
when dry, brushed carefully with a soft brush. If 
there be a doubt as to the purity of the silver, re- 
place the ammonia by sweet oil or alcohol. The 
ammonia and whiting are also good for gold. Jew- 
elry cleaned with water may be dried in boxwood 
sawdust. 

Care is necessary in the use of ammonia in or on 
"silver" topped articles, as vinaigrettes. These tops 



Protection ol 
Silverware. 



Silver 
Jewelry. 



Copper and 
Silver. 



116 



THE CHEMISTRY OF 



Brass, Copper. 



Oxidation of 
Metals. 



are often made of copper with a thin layer of silver. 
Whenever the ammonia remains upon the copper, 
it dissolves it, forming poisonous copper salts. 

Brass and copper must not be cleaned with am- 
monia unless due care is taken that every spot be 
rinsed and wiped perfectly dry. Nothing is better 
for these metals than the rotten-stone and oil of old- 
time practice. These may be mixed into a paste at 
the time of cleaning or be kept on hand in quantity. 
Most of the brass polishes sold in the market are 
composed of these two materials, with a little alco- 
hol or turpentine or soap, to form an emulsion with 
the oil. Oxalic acid may be used to clean these 
metals, but it must be rinsed or rubbed off com- 
pletely, or green salts will be formed. Copper or 
brass articles cleaned with acids tarnish much more 
quickly from the action of moisture in the air than 
when cleaned with the oil and soft powder. Small 
spots may be removed with a bit of lemon juice and 
hot water. An occasional rubbing with kerosene 
helps to keep all copper articles clean and bright. 
Indeed, kerosene is useful on any metal, as well as 
on wood or glass. ^ 

The presence of water always favors chemical 
change. Therefore iron a*hd steel rapidly oxidize 
in damp air or in the presence of moisture. All 
metallic articles may be protected from. such action 
by a thin oily coating. Iron and steel articles not in 
use may be covered with a thin layer of vaseline. 



COOKING AND CLEANING. 



11? 



Rust spots may be scoured off with emery and 
oil, covered with kerosene or sweet oil for some 
time and then rubbed hard, or in obstinate cases, 
touched with muriatic acid and then with ammonia, 
to neutralize the acid. 

A stove rubbed daily with a soft cloth and a few 
drops of kerosene or sweet oil may be kept black 
and clean, though not polished. Substances spilled 
on such a stove may be cleaned off with soap and 
water better than on one kept black with graphite. 

Nickel is now used in stove ornaments, in the 
bathroom, and in table utensils. It does not oxidize 
or tarnish in the air or with common use. It can 
be kept bright by washing in hot soap-suds and 
rinsing in very hot water. It may be rubbed with 
a paste of whiting and lard, tallow, alcohol or am- 
monia. 

Aluminum does not tarnish readily, and may be 
rubbed with the whiting or with any of the fine 
materials used for silver. It is darkened by 
alkalies. 
* Kitchen utensils, with careful use, may be kept 
clean by soap and water or a liberal use of am- 
monia. Fine sand-soap must occasionally be used 
when substances are burned on or where the tin 
comes in contact with flame. Kerosene is a good 
cleaner for the zinc stove-boards; vinegar and 
water, if there is careful rinsing afterward, or a 
strong solution of salt and water may be used. 



Iron-rust. 



Care of 
Stoves. 



Nickel. 



Aluminum. 



Kitchen 
Utensils. 



T 



CHAPTER IV. 
Laundry. 

HE health of the family depends largely upon 
the cleansing operations which belong to the 
laundry. Here, too, more largely perhaps than in 
any other line of cleaning, will a knowledge of 
chemical properties and reactions lead to econ- 
omy of time, strength and material. 

The numerous stains and spots on table linen 
and white clothes are dealt with in the laundry, 
and, also, all fabrics soiled by contact with the 
body. 

Body clothes, bed linen and towels become 
soiled not only by the sweat and oily secretions of 
the body, but also with the dead organic matter 
continually thrown off from its surface. Thus the 
cleansing of such articles means the removal of 
stains of varied character, grease and dust, and all 
traces of organic matter. 

The two most important agents in this purifica- 
tion are water and soap, 
water. Pure water is a chemical compound of two 

gases, hydrogen and oxygen (H 2 0). It has great 
solvent and absorbent power, so that in nature 
pure water is never found, though that which falls 



COOKING AND CLEANING. 119 

in sparsely-settled districts, at the end of a long 
storm, may be approximately pure. The first fall 
of any shower is mixed with impurities which have 
been washed from the air. Among these may be 
acids, ammonia and carbon in the form of soot 
and creosote. It is these impurities which cause 
the almost indelible stain left when rain-water 
stands upon window-sills or other finished wood. 

Cistern water, while soft, is liable to be colored wate r and Soft 
from shingles, paint or moss on the roof. Spring 
water and well water, having percolated a greater 
or less distance through the ground, are filtered, 
clear waters. But they have become mineralized 
to a degree because of the great solvent power 
of water. All ground waters contain more solid 
residue than rain water, and are more or less 
hard when they contain compounds of lime and 
magnesia. These form insoluble compounds 
with soap and give curd-like masses on hands 
or clothes. They waste the soap, therefore, in 
proportion to the amount present. 

The soft waters of the Atlantic seaboard use 
up very little soap. One pound of standard Cas- 
tile softens 409 gallons of water containing 
twenty parts per million of hardening sub- 
stances; one pound of Ivory soap softens 196 
gallons of the same water, and one pound of 
Gold Dust 65 gallons. 



120 



THE CHEMISTRY OF 



Temporary 
and 

Permanent 
Hardness. 



Soap. 



In case of a moderately hard water, not uncom- 
mon in wells, giving 200 parts hardness per 
million, one pound of Castile soap softens 60 
gallons, one pound of Ivory soap 29 gallons, and 
one pound of Gold Dust 24 gallons. Therefore 
the expense of securing a soft water supply is 
partly met by a saving in soap. 

Many hard waters may be softened by boiling. 
The gaseous carbon dioxide escapes and calcium 
carbonate falls to the bottom of the vessel. Or 
the excess gas may be taken up by lime water in 
the cold. Such hardness is often called tempo- 
rary, because it may be removed easily. 

Permanent hardness is given by sulphates, 
chlorides, nitrates of calcium, which require 
chemical action to remove. Such compounds 
are converted into carbonates by the addition of 
sal-soda, soda-ash, sodium carbonate, which gives 
the precipitate of calcium carbonate and the 
soluble sodium sulphate. Tri-sodium phosphate 
may be used instead of the carbonate, and 
calcium phosphate precipitated. 

In many parts of the country city supplies are 
"softened" by chemical treatment. 

Another important material used in the laundry 
is soap. "Whether the extended use of soap be 
preceded or succeeded by an improvement in any 
community — whether it be the precursor or the re- 



COOKING AND CLEANING. 121 

suit of a higher degree of refinement among the 
nations of the earth — the remark of Liebig must 
be acknowledged to be true, that the quantity of 
soap consumed by a nation would be no inaccur- 
ate measure whereby to estimate its wealth and 
civilization. Of two countries with an equal 
amount of population, the wealthiest and most 
highly civilized*will consume the greatest weight 
of soap. This consumption does not subserve sen- 
sual gratification, nor depend upon fashion, but 
upon the feeling of the beauty, comfort and wel- 
fare attendant upon cleanliness; and a regard to 
this feeling is coincident with wealth and civiliza- 
tion."* 

Many primitive people find a substitute for soap soap Substi. 
in the roots, bark or fruit of certain plants. Nearly 
every country is known to produce such vegetable 
soaps, the quality which they possess of forming 
an emulsion with oily substances being due to a 
peculiar vegetable substance, known as Saponin. 
Many of these saponaceous barks, roots and fruits 
are now used with good results — the "soap bark" 
of the druggist being one of the best substances 
for cleansing dress goods, especially black, wheth- 
er of silk or wool. 

The fruit of the soapberry tree — Papindus 
Saponaria — a native of the West Indies, is said to 

* Muspratt's Chemistry as Applied to Arts and Matiufactures. 



tutes. 



122 



THE CHEMISTRY OF 



Composition 
of Soaps. 



" Potash" and 
" Soda." 



be capable of cleansing as much linen as sixty 
times its weight of soap. 

Wood ashes were probably used as cleansing 
material long before soap was made, as well as 
long after its general use. Their properties and 
value will be considered later. 

Soaps for laundry use are chiefly composed of 
alkaline bases, combined with fatty acids. Their 
action is ''gently but efficiently to dispose the 
greasy dirt of the clothes and oily exudations of 
the skin to miscibility with, and solubility in wash 
water."* 

Oily matters, as we have seen, are soluble in cer- 
tain substances, as salt is soluble in water, and can 
be recovered in their original form from such solu- 
tions by simple evaporation. Others in contact 
with alkalies, form emulsions in which the sus- 
pended fatty globules make the liquid opaque, as 
in soapsuds. The soap is decomposed by water, 
the alkali set free acts upon the oily matter on the 
clothes, and unites with it, forming a new soap. 
The freed fatty acid remains in the water, causing 
the "milkiness," or is deposited upon the clothes. 

Certain compounds of two of the alkali metals, 
potassium and sodium, are capable of thus saponi- 
fying fats and forming the complex substances 
known as soaps. For the compounds of these al- 

* Chemistry applied to the Manufacture of Soaps and Candles,— Morfit. 



COOKING AND CLEANING. 123 

kalies employed in the manufacture of soap, we 
shall use the popular terms "potash" and "soda," as 
less likely to cause confusion in our readers' minds. 
Potash makes soft soap; soda makes hard soap. 
Potash is derived from wood ashes, and in the 
days of our grandmothers soft soap was the uni- 
versal detergent. Potash (often called pearlash) 
was cheap and abundant. The wood fires of every 
household furnished a waste product ready for its 
extraction. Aerated pearlash (potassium bicar- 
bonate), under the name of saleratus, was used for 
bread. Soda-ash was, at that time, obtained from 
the ashes of seaweed, and, of course, was not com- 
mon inland. 

The discovery by the French manufacturer, Le- 
blanc, of a process of making soda-ash from the 
cheap and abundant sodium chloride, or common 
salt, has quite reversed the conditions of the use 
of the two alkalies. Potash is now about eight 
cents a pound, soda-ash is only three. 

In 1824, Mr. James Muspratt, of Liverpool, first Manufacture 
carried out the Leblanc process on a large scale, 
and he is said to have been compelled to give 
away soda by ,he ton to the soap-boilers, before 
he could convince them that it was better than the 
ashes of kelp, which they were using on a small 
scale. The soap trade, as we now know it, came 
into existence after the soap-makers realized the 



124 THE CHEMISTRY OF 

value of the new process. Soda-ash is now the 
cheapest form of alkali, and housekeepers will do 
well to remember this fact when they are tempted 

to buy some new " ine" or "Crystal." 

In regard to the best form in which to use the 
alkali for washing purposes, experience is the best 
guide, — that is, experience reinforced by judg- 
ment; for the number of soaps and soap substi- 
tutes in the market is so great, and the names so 
little indicative of their value, that only general in- 
formation can be given. 

In the purchase of soap, it is safest to choose 
the make of some well-known and long-established 
firm, of which there are several who have a repu- 
tation to lose, if their products are not good ; and, 
for an additional agent, stronger than soap, it is 
better to buy sal-soda or soda-ash (sodium car- 
bonate) and use it knowingly, than to trust to the 
highly-lauded packages of the grocery. 
The use of Washing soda should never be used in the solid 

Washing ° 

Soda. form, but should be dissolved in a separate vessel, 

and the solution used with judgment. The in- 
judicious use of the solid is probably the cause of 
the disfavor with which it is often regarded. One 
of the most highly recommended of the scores of 
"washing compounds" formerly in the market, 
doubtless owed its popularity to the following di- 
rections: "Put the contents of the box into one 



COOKING AND CLEANING. 125 

quart of boiling water, stir well, and add three 
quarts of cold water; this will make one gallon. 
For washing clothes, allow two cupfuls of liquid 
to a large tub of water." 

As the package contained about a pound of 
washing soda, this rule, which good housekeepers 
have found so safe, means about two ounces to a 
large tub of water, added before the clothes are 
put in. 

Ten pounds of washing soda can be purchased 
of the grocer for the price of this one-pound pack- 
age with its high-sounding name. Nearly all the 
compounds in the market depend upon washing 
soda for their efficiency. Usually they contain 
nothing else. Sometimes soap is present and, 
rarely, borax. In one or two, a compound of am- 
monia has been found. 

Ammonia may be used with soap or as its sub- Ammonia 
stitute. The ammonia ordinarily used in the house- 
hold is an impure article and its continued use yel- 
lows bleached fabrics. The pure ammonia may be 
bought of druggists or of dealers in chemical sup- 
plies and diluted with two or even four parts of 
water. Borax, where the alkali is in a milder form 
than it is in washing soda, is an effectual cleanser, 
disinfectant and bleacher. It is more expensive 
than soda or ammonia, but for delicate fabrics and 
for many colored articles it is the safest alkali in 
use. 



126 



THE CHEMISTRY OF 



Removal of 
Stains. 



Fruit-Stains. 



Turpentine also is valuable in removing grease. 
A tablespoonful to a quart of warm water is a sat- 
isfactory way of washing silks and other delicate 
materials. It should never be used in hot water, 
for much would be lost by evaporation, and in this 
form it is more readily absorbed by the skin, caus- 
ing irritation and discomfort. 

Preparation for General Washing. 

White goods are liable to stains from a variety 
of sources. Many of these substances when acted 
upon by the moisture of the air, by dust, or al- 
kalies, change their character, becoming more or 
less indelible; colorless matters acquire color and 
liquids become semi-solid. All such spots and 
stains should be taken out before the clothes are 
put into the general wash to be treated with soap. 

Fruit stains are the most frequent and possibly 
the most indelible, when neglected. These should 
be treated when fresh. 

The juices of most fruits contain sugar in solu- 
tion, and pectose, a mucilaginous substance which 
will form jelly. All such gummy, saccharine mat- 
ters are dissolved most readily by boiling water, 
as are mucilage, gelatine and the like. To remove 
them when old, an acid, or in some cases, a 
bleaching liquid, like "chloride of lime" solution or 
Javelle water will be needed. 



COOKING AND CLEANING. 



127 



Stretch the stained part over an earthen dish and 
pour boiling water upon the stain until it disap- 
pears. How to use the acid and the Javelle water 
will be explained later on. 

Wine stains should be immediately covered 
with a thick layer of salt. Boiling milk is often 
used for taking out wine and fruit stains. 

Most fruit stains, especially those of berries, are 

bleached readily by the fumes of burning sulphur. 

S0 2 . These fumes are irritating to the mucous 

membrane and care should, therefore, be taken 

not to inhale them. Stand by an open window 

and turn the head away. Make a cone of stiff 

paper or cardboard or devote a small tin tunnel to 

this purpose. Cut off the base of the paper cone, 

leaving it level and have a small opening at the 

apex. On an old plate or saucer, place a small 

piece of sulphur, set it on fire, place over it the 

cone or tunnel, and hold the moistened stain over 

the chimney-like opening. Have a woolen cloth 

handy to put out the sulphur flame if the piece is 

larger than is needed. A burning match sometimes 

furnishes enough S0 2 for small spots. Do not get 

the burning sulphur on the skin. 

Medicine stains usually yield to alcohol. Iodine 
dissolves more quickly in ether or chloroform. 

Coffee, tea and cocoa stain badly, the latter, if 
neglected, resisting even to the destruction of the 



Use of Sul- 
phur Fumes 



Medicine. 



Tea, Coffee, 
Cocoa. 



128 THE CHEMISTRY OF 

fabric. These all contain tannin, besides various 
coloring matters. These coloring matters are 
"fixed" by soap and hot water. Clear boiling 
water will often remove fresh coffee and tea stains, 
although it is safer to sprinkle the stain with borax 
and soak in cold water first. (A dredging box 
filled with borax is a great convenience in the laun- 
dry.) Old cocoa and tea stains may resist the bo- 
rax. Extreme cases require extreme treatment. 
Place on such stains a small piece of washing- 
soda or "potash." Tie it in and boil the cloth for 
half an hour. It has already been said that these 
strong alkalies in their solid form cannot be al- 
lowed to touch the fabrics without injury. With 
this method, then, there must be a choice between 
the stain and an injury to the fabric, 
javeiie Water. An alkaline solution of great use and conven- 
ience is Javelle water. It will remove stains and 
is a general bleacher. This is composed of one 
pound of sal-soda with one-quarter pound of 
"chloride of lime" — calcium hypochlorite — in two 
quarts of boiling water. Let the substances dis- 
solve as much as they will and the solution cool and 
settle. Pour off the clear liquid and bottle it for 
use. Be careful not to let any of the solid portion 
pass into the bottle. Use the dregs to scour un- 
painted woodwork, or to cleanse waste pipes. 
When a spot is found on a white table-cloth, 



COOKING AND CLEANING. l2d 

place under it an overturned plate. Apply Javelle 
water with a soft tooth-brush. (The use of a brush 
protects the skin and nails.) Rub gently till the 
stain disappears, then rinse in clear water and 
finally in ammonia. "Chloride of lime" always 
contains a powerful acid, as well as some free 
chlorine. 

Blood stains require clear, cold or tepid water, Blood, 
for hot water and soap render the red coloring 
matter less soluble. When the stain is brown and 
nearly gone, soap and hot water may be used. 

Meat juice on the table linen is usually com- 
bined with more or less fat. This also yields most 
readily to the cold water, followed by soap. 

Stains made by mucus should be washed in am- 
monia before soap is added. When blood is mixed 
with mucus, as in the case of handkerchiefs, it 
is well to soak the stains for some hours in a solu- 
tion of salt and cold water — two tablespoonfuls to 
a quart. Double the quantity of salt for heavier 
or more badly stained articles. The salt has a dis- 
infecting quality, and its use in this way is a wise 
precaution in cases of catarrh. 

Milk exposed to the air becomes cheesy, and Milk, 
hot water with milk makes a substance difficult of 
solution. Milk stains, therefore, should be washed 
out when fresh and in cold water. 

Grass stains dissolve in alcohol. If applied im- Grass. 



130 THE CHEMISTRY OF 

mediately, ammonia and water will sometimes 
wash them out. In some cases the following meth- 
ods have proved successful, and their simplicity 
recommends them for trial in cases where colors 
might be affected by alcohol. Molasses, or a paste 
of soap and cooking soda, may be spread over the 
stain and left for some hours, or the stain may be 
kept moist in the sunshine until the green color 
has changed to brown, then it will wash out in 
clear water. 

Mildew. Mildew causes a spot of a totally different char- 

acter from any we have considered. It is a true 
mold, and like all plants requires warmth and 
moisture for its growth. When this necessary 
moisture is furnished by any cloth in a warm 
place, the mildew grows upon the fibres. During 
the first stages of its growth, the mold may be 
removed, but in time it destroys the fibres. 

Strong soapsuds, a layer of soft soap and pulver- 
ized chalk, or one of chalk and salt, are all effec- 
tive if, in addition, the moistened cloth be sub- 
jected to strong sunlight, which kills the plant 
and bleaches the fibres. Bleaching powder or 
Javelle water may be tried in cases of advanced 
growth, but success cannot be assured. 

°* 1 - Some of the animal and vegetable oils may be 

taken out by soap and cold water or dissolved in 
naphtha*, chloroform, ether, etc. 



COOKING AND CLEANING. 131 

Some of the vegetable oils are only sparingly 
soluble in cold, but readily soluble in hot alcohol. 
The boiling point of alcohol is so low that care 
should be taken that the temperature be not raised 
to the ignition point. 

Mineral oil stains are not soluble in any alkaline 
or acid solutions. Kerosene will evaporate in time. 
Vaseline stains should be soaked in kerosene be- 
fore water and soap touch them. 

Ink spots on white goods are the same in charac- ink. 
ter as on colored fabrics. Many of the present inks 
are made from aniline or allied substances instead 
of the iron compounds of the past. Aniline black 
is indelible; the colored anilines may be dissolved in 
alcohol. Where the ink is an iron compound the 
stain may be treated with oxalic, muriatic or hot 
tartaric acids, applied in the same manner as for 
iron-rust stains. No definite rule can be given, for 
some inks are affected by strong alkalies, others by 
acids, while some will dissolve in clear water. 

The present dyes are so much more stable than 
those of twenty-five years ago, that pure lemon 
juice or a weak acid like hydrochloric, has no effect 
upon many colors. Any acid should, however, be 
applied with caution. If the color is affected by 
acids, it may often be restored by dilute ammonia. 

The red iron-rust spots must be treated with acid. Red Ir ° Q - 
These are the result of true oxidation — the union 



rust. 



132 THE CHEMISTRY OF 

of the oxygen of the air with the iron in the pres- 
ence of moisture. The salt formed is deposited 
upon the fabric which furnishes the moisture. Or- 
dinary "tin" utensils are made from iron coated 
with tin, which soon wears off, so no moist fabric 
should be left long in tin unless the surface is entire. 

Iron-rust is, then, an oxide of iron. The oxides 
of iron, copper, tin, etc., are insoluble. The chlor- 
ides, however, are soluble. Replace the oxygen 
with the chlorine of hydrochloric acid and the iron 
compound will be dissolved. The method of apply- 
ing the acid is very simple. 

Fill an earthen dish two thirds full of hot water 
and stretch the stained cloth over this. Have near 
two other dishes with clear water in one and am- 
monia water in the other. The steam from the hot 
water will furnish the heat and moisture favorable 
for chemical action. Drop a little hydrochloric 
(muriatic) acid, HC1, on the stain with a medicine 
dropper. Let it act a moment, then lower the cloth 
into the clear water. Repeat till the stain disap- 
pears. Rinse carefully in the clear water and, 
finally, immerse in the ammonia water that any ex- 
cess of acid may be neutralized and the fabric pro- 
tected. 

Salt and lemon juice are often sufficient for a 
slight stain, probably because a little hydrochloric 
acid is formed from their union. 



COOKING AND CLEANING. 133 

Many spots appear upon white goods which re- Bluing, 
semble those made by iron-rust, or the fabrics 
themselves acquire a general yellowish tinge. This 
is the result of the use of bluing and soap, where 
there has been imperfect rinsing of the clothes. 
The old-time bluing was pure indigo. This is in- 
soluble, but, by its use, a fine blue powder was 
spread among the fibres of the cloth. It required 
careful manipulation, which it usually had. Indigo 
with sulphuric acid can be made to yield a soluble 
paste. This is the best form of bluing which can 
be used, for a very little gives a dark, clear blue to 
water, and overcomes the yellowish tinge which 
cotton or linen will acquire in time unless well 
bleached by sunshine. The expense and difficulty 
of obtaining this soluble indigo has led to the sub- 
stitution of numerous solid and liquid "blues" by 
the use of which the laundress is promised success 
with little labor. Most of these liquid bluings con- 
tain some iron compound. This, when in contact 
with a strong alkali, is broken up and the iron is 
precipitated. If, then, bluing be used where all the 
soap or alkali has not been rinsed from the clothes, 
this decomposition and precipitation takes place, 
and a deposit of iron oxide is left on the cloth. This 
must be dissolved by acid like any iron-rust. 

Some "blues" are compounds of ultramarine, a 
brilliant blue silicate of aluminum. These are gen- 



134 THE CHEMISTRY OF 

erally used in the form of a powder which is insol- 
uble, settles quickly and, thereby, leaves blue spots 
or streaks. It is very difficult to prevent these when 
insoluble powdered "blues" are used. This silicate 
combined with hydrochloric acid forms a jelly-like 
mass from which a white precipitate is formed. 
These ultramarine blues are sometimes recom- 
mended because of this white precipitate, obviating, 
as is said, the yellowish results of careless rinsing, 
inevitable when iron "blues" are used. The advice 
is misleading, for no precipitate is formed unless an 
acid be added. 

When solid bluing is used it should be placed in 
a flannel bag and stirred about in a basin of hot 
water. In this way only the finest of the powder is 
obtained. After this blued water is poured into the 
tub, it must be continually stirred, to prevent the 
powder from settling in spots or streaks upon the 
clothes. 
Bleaching. First, then, the removal of all dirt, and second, 

the removal, by thorough rinsing, of all soap or 
other alkalies used in the first process, and third, 
long exposure to air and sunshine should render 
the use of bluing unnecessary. The experience of 
many shows that clothes that have never been 
blued, never need bluing. In cities where conveni- 
ences for drying and bleaching in the sunshine are 
few, and where clear water or clear air are often un- 



COOKING AND CLEANING. 135 

attainable, a thorough bleaching two or three times 
a year is a necessity ; but in the country it is wiser to 
abolish all use of bluing and let the great bleacher, 
the sun, in its action with moisture and the oxygen 
of the air, keep the clothes white as well as pure. 

Freezing aids in bleaching, for it retains the 
moisture, upon which the sun can act so much the 
longer. The easiest household method of bleach- 
ing where clean grass, dew and sunshine are not 
available, is by the use of "bleaching powder." In 
the presence of water and weak acids, even carbonic 
acid, oxygen and chlorine are both set free from 
the compound. At the moment of liberation the 
action is very powerful. The organic coloring mat- 
ters present are seized upon and destroyed, thereby 
bleaching the fabric. 

Directions for the use of the powder usually ac- 
company the can in which it is bought. The woman 
who knows that the acid always present in the pow- 
der must be completely rinsed out or neutralized 
by an alkali, may use her bleaching powder with 
safety and satisfaction. 

All special deposits should be removed before General 
the general cleansing of the fabric is undertaken. 
Grease and other organic matters are the undesir- 
able substances which are to be disposed of in the 
general cleansing. Grease alone is more quickly 
acted upon by hot water than by cold, but other 



Cleansing. 



136 



THE CHEMISTRY OF 



Soaking. 



Boiling. 



Yellowness. 



organic matter is fixed by the hot water. There- 
fore, while hot water melts the grease quickly, the 
mixture may be thus spread over the surface and 
may not be removed by the soap. 

An effective method, proved by many housewives 
of long experience, is to soap thoroughly the dirti- 
est portions of the clothes, fold these together 
toward the center, roll the whole tightly, and soak 
in cold water. The water should just cover the 
articles. In this way the soap is kept where it is 
most needed, and not washed away before it has 
done its work. When the clothes are unrolled the 
dirt may be washed out with less rubbing. 

Too long soaking when a strong soap is used, 
which has much free alkali, would weaken the fab- 
ric. Judgment, trained by experience must guide 
in such cases, so that effective cleaning depends 
upon careful manipulation. 

Whether to boil or not to boil the clothes de- 
pends largely upon the purity of the materials used 
and the degree of care exercised. Many persons 
feel that the additional disinfection which boiling 
ensures is an element of cleanness not to be disre- 
garded ; others think it unnecessary under ordinary 
conditions, while others insist that boiling yellows 
the clothes. 

The causes of this yellowness seem to be: 



COOKING AND CLEANING. 



137 



Impure materials in the soap used ; 

The deposition, after a time, of iron from the 
water or the boiler; 

The imperfect washing of the clothes — that is, 
the organic matter is not thoroughly removed. 

The safest process seems to be to put the clothes 
into cold water with little or no soap, let the tem- 
perature rise gradually to the boiling point and 
remain there a few minutes. 

Soap is more readily dissolved by hot water than 
by cold, hence the boiling should help in the com- 
plete removal of the soap and may well precede the 
rinsing. 

Borax — A tablespoonful to every gallon of 
water — added to each boilerful serves as a bleacher 
and an aid in disinfection. The addition of the 
borax to the last rinsing water is preferred by 
many. In this case, the clothes should be hung out 
quite wet, so that the bleaching may be thorough. 

"Scalding," or the pouring of boiling water over 
the clothes is not so effectual for their disinfec- 
tion as boiling, because the temperature is so 
quickly lowered. 

The main points in laundry cleansing seem to 
be:— 

The removal of all stains; 

Soft water and a good quality of soap; 

The use of strong alkalies in solution only; 



Scalding. 



Necessities 
for Good 
Cleansing, 



138 



THE CHEMISTRY OF 



Linen. 



Not too hot nor too much water while the soap 
is acting upon the dirt; much water to wash in; 

Thorough rinsing, that all alkali may be re- 
moved; and that no dirty water remain: 

Long exposure to sunlight — the great bleacher 
and disinfectant. 

The fibres of cotton, silk and wool vary greatly 
in their structure, and a knowledge of this struc- 
ture, as shown under the microscope, may guide 
to proper methods of treatment. 

The fibres of cotton, though tubular, become 
much flattened during the process of manufacture, 
and under the microscope show a characteristic 
twist, with the ends gradually tapering to a point. 
It is this twist which makes them capable of being 
made into a firm, hard thread. 

The wool fibre, like human hair, is marked by 
transverse divisions, and these divisions are ser^ 
rated. These teeth become curled, knotted or 
tangled together by rubbing, by very hot water, or 
by strong alkalies. This causes the shrinking which 
should be prevented. When the two fibres are 
mixed there is less opportunity for the little teeth 
to become entangled and, therefore, there is less 
shrinkage. 

Linen fabrics are much like cotton, with slight 
notches or joints along the walls. These notches 
serve to hold the fibres closely together and enable 



COOKING AND CLEANING. 139 

them to be felted to form paper. Linen, then, will 
shrink, though not so much as wool, for the fibres 
are more wiry and the teeth much shorter. 

Silk* fibres are perfectly smooth, and when silk, 
rubbed, simply slide over each other. This pro- 
duces a slight shrinkage in the width of woven 
fabrics. 

All wool goods, then, require the greatest care $ as ^ of 
in washing. The different waters used should be of 
the same temperature, and never too hot to be 
borne comfortably by the hand. 

The soap used should be in the form of a thin 
soap solution. No soap should be rubbed on the 
fabric, and only a good white soap, free from rosin, 
or a soft potash soap, is allowable. Make each 
water slightly soapy and leave a very little in the 
fabric at the end, to furnish a dressing as nearly 
like the original as possible. 

Many persons prefer ammonia or borax in place 
of the soap. For pure white flannel, borax gives the 
best satisfaction, on account of its bleaching qual- 
ity. Whatever alkali is chosen, care should be ex- 
ercised in the quantity taken. Only enough should 
be used to make the water very soft. 

The fibres of wool collect much dust upon their 
tooth-like projections, and this should be thor- 
oughly brushed or shaken off before the fabric 
is put into the water. All friction should be by 



140 THE CHEMISTRY OF 

squeezing, not by rubbing. Wool should not be 
wrung by hand. Either run the fabric smoothly 
through a wringer or squeeze the water out, that 
the fibres may not be twisted. Wool may be well 
dried by rolling the article tightly in a thick dry 
towel or sheet and squeezing the whole till all 
moisture is absorbed. Wool should not be allowed 
to freeze, for the teeth will become knotted and 
hard. 

Linen, like wool, collects much dirt upon the 
surface which does not penetrate the fabric. Shake 
this off and rub the cloth as little as possible. 
Linen or woolen articles should not be twisted in 
the drying process, as it is sometimes impossible 
to straighten the fibres afterward, 
setting of Colored cottons should have their colors fixed 

Colors. 

before washing. Salt will set most colors, but the 
process must be repeated at each washing. Alum 
sets the colors permanently, and at the same time 
renders the fabric less combustible, if used in 
strong solution after the final rinsing, 
very Dirty Dish cloths and dish towels must be kept clean 

Aiticles. 

as a matter of health, as well as a necessity for 
clean, bright tableware. The greasy dish cloth 
furnishes a most favorable field for the growth 
of germs. It must be washed with soap and hot 
water and dried thoroughly each time. All such 
cloths should also form a part of the weekly 



COOKING AND CLEANING. 



141 



wash and be subjected to all the disinfection pos- 
sible, with soap, hot water and long drying in sun- 
shine and the open air. Beware of the disease- 
breeding, greasy and damp dish cloth hung in a 
warm, dark place! 

Oven towels, soiled with soot and crock, may be 
soaked over night, or for some hours, in just kero- 
sene enough to cover, then washed in cold water 
and soap. 

With very dirty clothes or for spots, where hard 
rubbing is necessary, much strength may be saved 
by using a scrubbing brush. 

Laundry tubs should be carefully washed and 
dried. Wooden tubs, if kept in a very dry place, 
and turned upside down, may have the bottoms 
covered with a little water. 

The rubber rollers of the wringer may be kept 
white by rubbing them with a clean cloth and a 
few drops of kerosene. 

All waste and overflow pipes, from that of the 
kitchen sink to that of the refrigerator, become 
foul with grease, lint, dust, and other organic mat- 
ters that are the result of bacterial action. They 
are sources of contamination to the air of the en- 
tire house and to the food supply, thereby endan- 
gering health. All bath, set-bowl and watei closet 
pipes should be flushed generously once a day, at 
least, the kitchen sink pipe with clear boiling 



Care of Laun« 
dry Furni- 
ture. 



Care of 
Plumbing. 



142 THE CHEMISTRY OF 

water; and once a week all pipes should have a 
thorough cleaning- with a strong boiling solution 
of washing-soda and a monthly flushing with caus- 
tic potash. The plumbers recommend the "stone" 
or crude potash for the kitchen pipe. This, is 
against their own interests, for many a plumber's 
bill is saved where the housewife knows the dan- 
ger and the means of prevention of a grease-coated 
sink drain. The pipe of the refrigerator should be 
cleared throughout its entire length with the soda 
solution. Avoid any injury to the metallic rims of 
the waste pipes by using a large tunnel. 

Old-fashioned styles of overflow pipes retain a 
large amount of filth, and it is very difficult to dis- 
lodge it. A common syringe may be devoted to 
this purpose. By its patient, frequent use even this 
tortuous pipe may be kept clean. 

Ideal Cleanness. 
Sanitary Ideal cleanness requires the cleanness of the in- 

Clcanness. n 

dividual, of his possessions, and of his environ- 
ment. Each individual is directly responsible for 
his personal cleanness and that of his possessions; 
but over a large part of his environment he has 
only indirect control. Not until direct personal 
responsibility is felt in its fullest sense, and exer- 
cised in all directions toward the formation and 
carrying out of sufficient public laws, will sanitary 



COOKING AND CLEANING. 



143 



cleanness supplant the cure of a large number of 
diseases by their prevention. 

Many of the diseases of childhood are directly 
traceable to uncleanness, somewhere. By these dis- 
eases the system, is often so weakened that others 
of different character are caused which, though 
slow in action, may baffle all science in their cure. 

The necessity of forming systematic habits of 
cleanness in the young is the first step toward sani- 
tary health. They should, then, step by step, as 
they are able to grasp the reasons for the habits, 
be educated in all the sciences which give them 
the knowledge of the cause and effects of un- 
cleanness, the methods of prevention and removal, 
and the relation of all these to building laws and 
municipal regulations. 

The first environment to be kept clean is the 
home. But personal cleanness and household 
cleanness should not be rendered partially futile by 
unclean schoolhouses, public buildings and streets. 

The housekeeping of the schoolhouses, especially, 
should be carried on with a high regard to all 
hygienic details, since here the degree of danger 
is even greater than in the home. In public 
schoolhouses the conditions favorable to the pres- 
ence of disease germs abound. If present, their 
growth is rapid, and the extent of contagion be- 
yond calculation. The cooperation of all most in- 



Personal 
Cleanness. 



School-house 
Sanitation. 



144 COOKING AND CLEANING. 

terested — pupils and teachers — should be expected 
and required as firmly as their cooperation in any 
other department of education. 
nes b s lic Qean " The sanitary condition of every school building 

should be a model object lesson for the home; then, 
instruction in personal cleanness will carry the 
weight of an acknowledged necessity. 

Schoolhouses which are models of sanitary clean- 
ness will cause a demand for streets and public 
conveyances of like character; then all public build- 
ings will be brought under the same laws of evi- 
dent wisdom. 

Not till the right of cleanness is added to the 
right to be well fed, and both are assured to each 
individual by the knowledge and consent of the 
whole people, can the greater gospel of prevention 
make good its claims. 



CHAPTER V. 
Chemicals and Their Use in the Household. 

EVERY woman, whether she knows it or not, ExpSSLts 
is every day performing simple experi- in the Home - 
ments in chemistry. Every match that is lighted, 
every use of soap on the body, the clothes or the 
utensils, depends upon chemical laws for the 
reactions which take place. 

There is no process of cooking or cleaning 
that does not rest upon a foundation of chemical 
or physical law. Therefore every house is a 
laboratory. Each is presided over by a director 
of greater or less intelligence. 

When intellectual interest and manual dex- 
terity unite, "drudgery" is eliminated. 

There may be, too, at all times an attitude of 
discovery. Many of the most important chem- 
ical processes have been found out, it is said, 
accidentally. 

In most persons an experiment awakens in- 
terest. The housewife should be a cautious 
experimenter. 

An understanding of simple chemical reac- 
tions tends also to economy in household 
management. 



146 THE CHEMISTRY OF 

The thrifty housewife may not only save many 
dollars by restoring tarnished furniture and 
stained fabrics, but may also keep her belongings 
fresh and "as good as new" by the judicious use 
of a few chemical substances always ready at her 
hand. 

It is essential, however, that she know their 
properties and the effect they are likely to have 
on the materials to be treated, lest more harm 
than good result from their use. A good exam- 
ple is the instant disappearance of all red iron- 
rust stains when treated with a drop of hydro- 
chloric acid. If, however, the acid is not com- 
pletely washed out, the fabric will become eaten, 
and holes will appear, which, in the housekeeper's 
eye, are worse than the stains. This danger may 
be entirely removed by adding ammonia to the 
final rinsing water, which neutralizes any remain- 
ing acid, and the stained tray-cloth or sheet is 
perfectly whitened. 

It is well that the household laboratory should 
be supplied with the following substances. Not 
all of these are strictly chemicals, but they are 
included by courtesy, as it were, because so 
closely connected with the chemical reactions. 
Many of them act only mechanically. 
Alkalies. I. Alkalies — substances with a soapy feeling 

and which turn red litmus blue. In solutions 



COOKING AND CLEANING. 147 

they neutralize the effects of acids. When the 
neutralization is complete the solution is said to 
be neutral, and it will not change the color of 
litmus. This neutral substance is a chemical 
salt. 

Alkalies, except ammonia, injure wool fibres, 
hardening, roughening and shrinking them, 
while the caustic alkalies dissolve them. Only 
weak alkalies should be used on linen or silk. 

I. Potassium hydroxide, KOH, Caustic pot- Caustic Potash. 

ash. This can be bought in solid form to use in 
drains for removing grease. It forms a soap, 
which must be washed out of the pipes by thor- 
ough flushing. It is one of the strongest alkalies 
and must be used with caution. It is dissolved 
in water with the evolution of great heat, caus- 
ing rapid boiling. Spatters from it on fabrics 
are liable to burn holes, on wood will darken the 
color, and on the flesh may cause deep burns. 
When got upon the flesh or upon fabrics it 
should be quickly washed off and, if necessary, 
treated with vinegar. It is usually bought in 
cans as " concentrated lye."* It combines with 
fat to make soft soap. 

Potassium is a common ingredient of inland 
vegetation. Caustic potash is derived from wood 
ashes. By adding water to wood ashes, potash 

* Today, however, this is more often caustic soda than potash. 



148 THE CHEMISTRY* OF 

(carbonate of potash) is dissolved and the result- 
ing liquid, lye, may t>e used for purposes of 
cleansing. 

Many a country housewife " sweetens" the 
tainted pork barrel, the butter firkin or pie plate 
by soaking or boiling it with wood ashes. Ran- 
cid fats are acid. This acidity can be neutral- 
ized by the alkali. 

Potash is often used to soften paint, shellac 
and other woodwork finishes, to facilitate their 
removal before refinishing. This has the disad- 
vantage that the wood is darkened by the alkali 
and the grain is raised. 
Caustic soda. 2. Sodium hydroxide, NaOH, caustic soda. 

This compound resembles caustic potash, is ef- 
fective in slightly less degree for the same pur- 
poses ; and, being cheaper, is much more exten- 
sively used. The element sodium is common in 
all marine and seashore plants, and is the metal 
in common salt, from which it is now prepared. 
Soda Ash. 3. Sodium carbonate, Na 2 C0 3 , soda-ash 

(originally from the ashes of seaweed). When a 
hot solution of soda-ash is cooled, a crystalline 
form is left known as sal-soda, washing soda, 
soda crystals. The crystals lose water when ex- 
posed to the air and crumble to powder. This 
powder is, therefore, stronger than the crystals. 

Sal-soda is used most commonly in softening 



COOKING AND CLEANING. 149 

hard water, for keeping the plumbing pipes free 
from grease and to remove grease and hardened 
food from cooking utensils. A convenient way 
to prepare sal-soda for general use is to put one 
pound of the ash in one quart of water. Let 
this boil until the soda is dissolved. Bottle when 
cold. It is the second strongest alkaline cleaner, 
cheaper and more safely used than potash. 

4. Sodium bicarbonate, NaHCO s , cooking cooking soda. 
soda, carbonated soda-ash. In cooking it is used 

to neutralize acids, to aerate dough and to pro- 
duce effervescence in acid solutions by liberating 
carbon dioxide. This is the saleratus of today. 
The true saleratus or "pearlash" used seventy- 
five years ago was the corresponding potassium 
salt, KHCO3. This was often obtained by burn- 
ing corncobs, mixing the ashes with water and 
allowing the solution to evaporate to dryness. 

In cleaning, sodium bicarbonate gives a mildly 
alkaline action when dissolved in water. With 
kerosene it is nearly insoluble and therefore 
gives a soft friction. Used in this way it is 
effective in scouring plumbing fixtures, where 
the insoluble whiting might clog the pipes. For 
cleaning purposes, the choice between borax and 
bicarbonate would be one of their relative cost. 

5. Borax, Na 2 B 4 4 . A weakly alkaline sub- Borax. 
stance, most useful with hard water, as a 



150 THE CHEMISTRY OF 

bleacher and as an antiseptic. It is much more 
expensive than sal-soda, but is less liable to injure 
fabrics and to irritate the skin. Its action on 
colors is less than that of ammonia. 

6. Ammonia. The gas NH S is dissolved in 
water in varying proportions, forming ammo- 
nium hydroxide, or aqua ammonia, NH 4 OH. It 
is the only volatile alkali. It is a useful sub- 
stance in nearly all cleaning processes, and to 
neutralize acids. 

"Household ammonia" is subject to impurities 
due to processes of manufacture. These often 
fade colors or cause white materials to turn yel- 
low. It is safer and cheaper to buy the concen- 
trated ammonia from a druggist or a dealer in 
chemicals and add the water at home. This con- 
centrated ammonia may be diluted one-half to 
one-sixth and yet be sufficiently strong for most 
uses. 

It loses strength rapidly when open to the air, 
therefore it should be bought in quantities pro- 
portioned to its use, diluted one-half or more 
and kept carefully corked. A glass stopper is 
best, although rubber will serve. Cork is acted 
upon by the fumes and will color the ammonia. 
If the glass stopper tends to stick, it may be kept 
slightly smeared with vaseline. 

Ammonia should not be used on brass or 



COOKING AND CLEANING. 151 

copper, as it eats them rapidly. It discolors 
aluminum; but the resultant compound is not 
injurious. 

7. Soaps. Hard soap is sold in small cakes, Soaps - 
shavings or powder; soft soap in semi-liquid, 

or liquid soap solutions. There are many grades 
from those that are neutral, like the best toilet 
soaps, to those that have much free alkali. The 
free alkali hastens the action, but is injurious to 
the skin and to many other materials. Soap and 
water has a greater solvent power than water 
alone. 

8. Ox-gall, the liquid contents of the gall- Ox-Gail, 
bladder of beef creatures, is a natural soap. It 

is excellent for cleaning colored fabrics. It may 
be used clear or with tepid water. It decomposes 
readily and, therefore, must be used while fresh. 

II. Acids — substances with a sour taste and Acids - 
which change blue litmus red. An acid will also 
liberate carbon dioxide from cooking or washing 
soda. In general, weak acids lighten the color 
of wood, while strong acids burn it. Acids act 
injuriously on all metals if allowed to remain in 
contact with them. The metallic salts that are 
formed are often very poisonous. 

When used with caution acids are effectual in 
removing iron and fruit stains. They remove 
color from some fabrics. 



152 



THE CHEMISTRY OF 



Acetic Acid. 



Lactic and 
Citric Acids. 



Dilute, cold, acid solutions do not readily in- 
jure cotton or linen, while hot, strong solutions 
injure the fibre. No acid should be allowed to 
dry upon cloth. 

I. Acetic acid, C 2 H 4 2 , is the acid of vinegar 
and for many purposes it may be used in this 
form. For delicate processes, however, the other 
substances present may stain or interfere with 
the action, so that the pure acetic acid, much 
diluted, is better. It is volatile, therefore any 
excess is not likely to injure the fabric by con- 
centration in it on drying, as will hydrochloric 
and oxalic acids. While acids clean copper and 
brass quickly by combining with the tarnishing 
salts, thus exposing a fresh surface, this new 
surface soon tarnishes again, and the process 
must be repeated. If any acid remains, as it is 
likely to do in seams and grooves, metallic salts 
will be formed. Copper acetate, which is formed 
when brass or copper is treated with vinegar, is 
very dangerous. 

Sour milk contains lactic acid ; lemons, citric 
acid, and this is perhaps the best natural acid to 
use for cleaning purposes. It should be used 
with caution, however, as it is strong enough to 
affect some colors and reacts with metals, as 
copper, brass and iron. Rhubarb, tomatoes, sor- 
rel, etc., contain acid principles. They can be 



COOKING AND CLEANING. 153 

used in emergencies and are less liable to "eat" 
fabrics. 

2. Oxalic acid, H 2 C 2 4 , is found naturally in OxaikAcid. 
some plants, as oxalis and sorrel. It is bought 
in crystals, which are quickly soluble in hot and 
more slowly in cold water. It is very useful in 
removing stains from white fabrics and may be 
used on some colors (any acid to be used on 
colored fabrics should be tested first on a piece 
of the goods or on some hidden part, as a seam). 

Hot solutions of oxalic acid are more effective 
than cold. When very strong it makes the finger 
nails brittle and may irritate the skin tempo- 
rarily. It must be labeled "Poison," and should 
be kept out of the reach of children. 

N OTE —The strong acids destroy the coats of the stomach and there- 
fore are poisonous in a general sense, although not in the strict sense in 
which strychnine is. 

3. Tartaric acid, H 2 (C 4 H 4 6 ), the acid of Tartaric Add. 
cream of tartar, and prepared from it by treat- 
ment with milk of lime, is one of the safest acid 

agents. The Rochelle salt of Seidlitz powders 
is a sodium potassium tartrate. In "soda pow- 
ders" one paper contains tartaric acid, the other 
sodium bicarbonate. The crude tartar or argol 
is formed as a hard crust or deposit on the 
bottom and sides of vessels in which wine is 
manufactured. 

4. Hydrochloric or muriatic acid, HC1, most K° chloric 



154 THE CHEMISTRY OF 

valuable for removing iron stains from fabrics 
and other materials. It sometimes injures silk 
and must be used with caution on colored goods. 
A twenty per cent solution is effective, but it will 
lose its strength unless very tightly corked with 
glass or rubber. The fumes escaping around the 
stopper will rust metals and " eat "fabrics even 
at some distance. 

Whenever this acid is used there should be 
thorough rinsing of the fabric in water, prefer- 
ably warm, and then neutralization in ammonia. 

Bleachers. \\\ m Bleachers. These are sometimes used 

to remove color from colored fabrics, but more 
often to remove the yellow or brownish discol- 
oration from fabrics which are naturally yellow 
or which were originally white. 

Sometimes the action is the result of adding 
oxygen to the coloring matter; sometimes it 
takes oxygen away. In both cases colorless com- 
pounds are left, and in both cases moisture is 
necessary. 

Sunshine. The best bleacher is sunshine with moisture. 

The action here is very complex, resulting in the 
formation of ozone, but there is never any harm 
to the fabric. The best way of using " Nature's 
bleach" is to spread the fabrics on the grass, wet 
them frequently with soapy, or better with borax 
or ammonia water, leave out over night for the 



COOKING AND CLEANING. 155 

dew to form on them, turn occasionally that all 
parts may be acted upon, and continue this until 
the desired whiteness is reached. 

In "dog days," however, the fabrics must be 
carefully watched, else they will mildew. 

The best time for grass bleaching is during the 
long days of June. 

If grass is not available, any other means by 
which the wet cloth can be exposed to direct sun- 
shine will answer. The wet, yellow handkerchief 
or lace may be kept by the sunny window until 
bleached. 

Cloth laid on the snow bleaches fairly well. 
When clothes freeze the moisture is retained so 
much longer that even in the short, sunny days 
of winter considerable bleaching may be done. 

All bleaching with chemicals is attended with 
danger to the fibre ; but it is so much more rapid 
and so convenient a method that not only its 
dangers should be understood, but also how to 
obviate them. 

When the chemical has completed its action 
with the coloring matter, it attacks the fibre 
unless quickly removed. 

i. Hydrogen peroxide, H 0„, may be pur- Hydrogen 

i i r i« ^,i • Peroxide. 

chased as a live per cent liquid. This is a power- 
ful oxidizing agent. It loses the extra atom of 
oxygen readily and should be kept in a dark place, 
preferably closed with a rubber stopper, 



156 



THE CHEMISTRY OF 



Sulphur 
Dioxide. 



Chloride of 
Lime. 



It may be safely used with all fibres, being 
especially good for wool. The bleaching action 
is permanent. 

It is an excellent disinfectant for wounds, sore 
throat, etc. 

2. Sulphur dioxide, S0 2 , is made by burning 
sulphur in the air. With moisture the dioxide 
forms sulphurous acid, H 2 SO s . 

This is effective on moist silk, wool, straw and 
paper. The fumes should not be breathed. The 
country housewife attaches the wet, yellowed 
straw hat to the bottom of a barrel, which is 
then inverted over a small kettle of coals and 
sulphur. 

This is much less destructive to the fibre than 
chloride of lime, but the color often returns. 
The fumes from a burning match held under 
the wet hand will remove the purple stains left 
from black kid gloves. They are also very effect- 
ive for blueberry and blackberry stains. 

The common sulphur candle is a convenient 
means of obtaining sulphur fumes. They may 
be readily concentrated by inverting over the 
candle a paper, cardboard or other funnel. 

3. Calcium hypochlorite is called bleaching 
powder and "chloride of lime." Its composition 
is not definitely known, but approximately is 
given as CaOCL. A similar compound is some- 



COOKING AND CLEANING. m 157 

times called "chlorinated lime." (Chlorinated 
soda is also on the market.) 

When treated with acids this gives off chlorine, 
freely. The carbon dioxide in the air liberates 
it slowly, so that its very presence in the house 
(or its use as a deodorizer or disinfectant) is a 
prolific source of rust and deterioration of cotton 
and other fabrics. 

Whether used for general bleaching or in the 
removal of stains, thorough rinsing and neutral- 
ization in ammonia water must follow, else the 
fabric will suffer. 

4. Javelle water, really sodium hypochlorite, J avelle Water - 
is a compound made by mixing "chloride of 

lime" and sodium carbonate. It is excellent 
for the treatment of old or obstinate stains as 
well as a general bleach. Ammonia or sodium 
hyposulphite should be used afterwards. 

5. Sodium thio sulphite — called also hyposul- Hyposulphite, 
phite, Na 2 S 2 3 + 5H 2 0, the "hypo" of the pho- 
tographer — is especially effective in removing 

the marks of indelible ink containing silver 
nitrate. 

6. Borax (see page 149). Borax - 
IV. Solvents. For grease there are naphtha, Solvents - 

benzine, gasoline, ether, chloroform, extremely 
volatile ; kerosene, turpentine, carbon tetrachlo- 
ride, coal tar benzine (C H 6 ), alcohol less volatile. 



158 . THE CHEMISTRY OF 

The vapors of all these substances are heav- 
ier than air, therefore sink. They should be used 
out-of-doors or by an open window, and never 
where there is any fire. There should be a cur- 
rent of air near the floor to ensure quick removal 
of the vapor. 

Turpentine is a resinous oil which serves as a 
solvent for paint, grease, tar and wax. Mixed 
with oil, preferably boiled linseed, it makes the 
best general furniture polish. It cleans more 
readily than kerosene, but does not give so good 
a polish. It removes ink stains from polished 
woods, from which it usually removes the gloss 
and should be followed by oil and hard rubbing. 
It will remove some inks from colored fabrics. 
In the laundry it tends to whiten clothes. When 
fresh it is clear and has little odor. When ex- 
posed to the air it takes up oxygen, darkens and 
thickens. This should not be used on fabrics, as 
it will itself stain. 

The vapors of chloroform and carbon tetra- 
chloride are non-inflammable and non-explo- 
sive. These, like ether, should be used where 
there is a good draft, as they produce anaesthesia. 
Chloroform is least likely to injure colors, 
although ether is usually safe. 
Oils. V. Oils. The most common vegetable oils 

are raw and boiled linseed, sweet or olive and 



COOKING AND CLEANING. 159 

cottonseed. They are all good for polishing 
woodwork and metals, for softening and bright- 
ening leather (particularly olive oil), to imbed 
frictional materials, as emery for iron, rotten- 
stone or tripoli for brass and copper; to soften 
pitch, tar, etc. 

Mineral oils are kerosene, an excellent cleaner, 
a good polisher, a solvent of vaseline, an insecti- 
cide ; and paraffin oil — less odorous than kero- 
sene but a little more expensive. Mixed with 
turpentine in equal parts it makes an excellent 
furniture polish for very light-colored woods 
when the linseed oil, which is usually used, might 
darken them too much ; coal tar benzine, C 6 H 6 , 
is excellent for removing grease, pitch and resin. 

VI. "Alcohols." Ethyl alcohol, C 2 H 5 OH, A1 «> hols - 
"grain alcohol," is valuable for removing stains. 
"Wood alcohol," CH 3 OH, is less effective and is 
poisonous when taken internally. It should 
therefore be labeled " Poison." 

Denatured alcohol may or may not be effective 
for use on fabrics, according to the foreign 
substances which have been added. 

Alcohol dissolves shellac and turns varnish 
and wax white. White stains on shellaced wood 
are removed by gentle tapping with a bit of 
flannel cloth wet in alcohol. 

VII. Stiffening Agents. Starch is obtained stiffening 

° ° Agents. 



160 THE CHEMISTRY OF 

from many plants, but chiefly for laundry uses 
from corn, wheat and rice. Potatoes and sago 
also furnish it. Wheat starch is most satisfac- 
tory for general purposes. It gives a more flex- 
ible stiffness and smoother surface than corn 
starch, 
starch. Rice starch is excellent for delicate work, as 

fine dress goods and laces. As was shown in the 
previous pages, uncooked starch is not soluble in 
water. 

In cold starching the spaces between the 
threads of the fabrics are filled and the surface 
coated with the fine powder. The heat of the 
iron with the moisture brings about the change 
of condition and great stiffness results. 

It is better for general stiffening purposes to 
cook starch thoroughly before applying it to 
the fabric. As this cooking may caramelize a 
part, making it slightly yellow, a very little blu- 
ing may be added to counteract it. Thoroughly 
cooked starch should not stick to a hot iron ; but 
a little turpentine, wax or paraffin added helps 
the iron to slip over the surface more readily 
and adds some gloss. 

A little borax in the starch preserves the stiff- 
ness of starched articles when they are exposed 
to dampness," as at the seashore. 

Starched articles should not freeze before 
ironing. 



COOKING AND CLEANING. 161 

Prepared starches are sometimes made soluble 
by treatment with acids. These frequently affect 
the color of colored fabrics upon which they are 
used. 

Some also have borax or other alkali combined 
with them, and these also change colored fabrics. 

Blues, pinks and greens seem to be most sus- 
ceptible to these changes. If a blue is turned 
pinkish it may be well to add a little ammonia or 
borax to the starch; if pink is turned blue, add 
a little acid — clear vinegar or lemon juice. Per- 
haps the safer way is better, i. e., to use only the 
starch bought in bulk. 

Gum arabic, sugar, glue and gelatine are all other Agents, 
valuable for stiffening thin, delicate fabrics. 

Black laces, straw hats and ribbons are often 
stiffened sufficiently by rinsing them in alcohol 
and water. This slightly dissolves the still 
remaining stiffening. 

VIII. Bluings. These substances are used to Bluings, 
counteract or cover by their blue color the yel- 
lowness which results from imperfect washing or 
rinsing ; from too much or too strong alkali ; 
from iron in the water ; or from the action of the 
air or the absence of light, as when fabrics are 
unused and stored in dark places. Blue and 
yellow, however, do not make white. The color 
which results from the use of bluing varies from 
gray to green or blue when compared with white. 



162 THE CHEMISTRY OF 

The bluings act either mechanically by leaving 
a fine, impalpable powder among the meshes as 
ultramarine, or by a tint absorbed by the fibre 
from the blue solution. 

The public laundries use almost exclusively an 
aniline blue. This may be purchased solid or 
liquid and is a real dye. It requires an acid 
medium before it will set, and too many times 
this acid injures the fabrics. As it is a dye, it is 
difficult to remove the effects when too much is 
used. 

A good blued water is excellent for preserving 
the original color of blue fabrics. It also im- 
proves the appearance of dull or blue-black 
goods. 
Frictionai IX. Frictional Materials. These do not act 

chemically, but are important agents in the proc- 
esses of cleaning and preservation. They may 
be combined with soap, oils or other substances 
into solid or paste-like form. 

The best of the frictional materials are whit- 
ing, silicon, rouge, rotten-stone, tripoli, emery, 
pumice and common sand of various degrees of 
coarseness. Coal ashes, sifted, make an excellent 
frictional material. 

The commercial, prepared forms are often 
more convenient for use, but much more expen- 
sive; and any undesirable, sharp, gritty parti- 



Materials. 



COOKING AND CLEANING. 163 

cles, which would scratch or mar the article 
scoured, might not be detected until the injury 
occurred. Again the temptation is strong to put 
into these manufactured materials substances 
which will "take hold quickly," or "do the work 
in half the time," and these are apt to be injuri- 
ous to the articles cleaned. 

X. Absorbent Materials. Pipe clay, Fuller's ^sorbent 
earth, French chalk, are perhaps the best. It 
should be remembered that starch, flour, meal, 
sawdust, blotting paper and similar materials 

have much absorbent power. These extract 
liquids mechanically and therefore do not affect 
the fabric. 

XI. Miscellaneous: i. Alum, a crystalline Alum, 
double salt of potassium and aluminum. It is 
used for clearing water from suspended organic 
matter by coagulation, for "fixing" colors and 

for making cotton fabrics less inflammable. 

For the laundry, two ounces of alum to a 
gallon of water is sufficient. Less than this will 
set most colors. 

Sugar of lead, lead acetate, fixes colors, 
but it is a strong poison and its use is not 
recommended. 

2. Litmus paper is convenient for testing Litmus Paper, 
solutions, either for acidity or alkalinity. The 
red paper will give a rough test of free alkali if 



164 THE CHEMISTRY OP 

it be moistened and laid on soap ; the blue paper 
for acid, on bread dough, etc. 

One piece may be used alternately in acid and 
alkaline solutions an indefinite number of times, 
salt. 3. Sodium chloride, NaCl, common salt, is 

used as a condiment, an antiseptic ; for friction 
and absorption; to remove silver sulphide (see 
p. 112); in the laundry for fixing colors tem- 
porarily and to aid in removing red wine, blood 
and iron-rust stains. 

Its action in setting colors is chiefly in decreas- 
ing the solvent power of the water. 

New goods, liable to fade, should be rinsed in 
it before being washed with soap. 



CHAPTER VI. 
Antiseptics, Disinfectants, Insecticides 

FUNDAMENTALLY and ordinarily clean- 
ness depends upon the prevention or re- 
moval of unclean conditions — both the presence 
of the living agents and that of the organic 
matter on which they feed. Rosenau says: 
"While the old idea that filth and unsanitary 
conditions breed disease de novo is wrong, it is 
nevertheless true that these conditions keep 
the infectious principles alive and favor their 
propagation." 

When infectious material is present, danger 
is imminent and safety may require that the 
living agents be destroyed that they be not 
spread about. 

If their growth can be prevented, a measure Antisepsis, 
of safety is attained. This is the condition of 
antisepsis. It is brought about by producing 
unfavorable conditions of growth. For this pur- 
pose positive or negative means may be em- 
ployed. The addition of sugar in preserves 
lessens the air and water supply of the ferments ; 



Disinfection. 



166 THE CHEMISTRY OF 

salt withdraws moisture; drying by any means, 
as the admission of sunlight and fresh air — 
these are all antiseptic measures. Or, substances 
may be applied which will retard or prevent the 
growth of the germs. These are called antisep- 
tics; soap, salt, strong acids, essential oils, 
smoke, all act in this manner. Weak solutions 
of substances which when strong will kill the 
germ usually prevent or retard its action. Boric 
acid is one of the best of the chemical antiseptics. 

But this is only partial immunity. Safety re- 
quires that the living agent of infection be killed. 
This is the office of disinfection. Substances 
which kill disease germs are called disinfectants. 
All disinfectants are germicides. Sterilization 
means the absence of all life, whether by proc- 
esses of removal or death. This is a much 
broader term than disinfection. Disinfectants 
may kill the pathogenic forms, while many harm- 
less ones remain. Sterilization would affect all. 
This is seldom necessary. The state of asepsis 
is equivalent to sterilization. 

An ideal disinfectant will destroy the patho- 
genic germs without injury to the infected mate- 
rial. This may be difficult to find, as no one 
agent is applicable either to all germs or to all 
materials. Direct sunshine is Nature's best and 
cheapest disinfectant. It will, however, fade 



COOKING AND CLEANING. 167 

color; but this should not be considered where 
infectious material is liable to be present. It 
destroys the superficial spores as well as the 
active forms ; but cannot penetrate opaque ob- 
jects, and not deeply into solutions. It is most 
effective, then, on surfaces. 

Dry heat, 300 F., is sufficient to destroy the Dry Heat, 
common pathogenic germs, but this is far above 
what can be used, without injury, in most cases. 

Dry heat is not so effective as moist heat. 
Anything that can be boiled or steamed can be 
most surely made safe. 

In "Disinfection and Disinfectants," Dr. Ros- 
enau says, regarding dry heat, boiling and 
steam : 

"Most materials will bear a temperature of 
110° C. (about 230 F.) without much injury, 
but when this temperature is exceeded, signs of 
damage soon begin to show. Scorching occurs 
sooner in woolen materials, such as flannels and 
blankets, than with cotton and linen. The over- 
drying renders most fabrics very brittle, but this 
injury may be lessened by allowing the materials 
which have been subjected to dry heat to remain 
in the air long enough to regain their natural 
degree of moisture before manipulating them. 

"The ordinary household cooking oven is as 
good as any specially contrived apparatus for the 
disinfection of small objects by dry heat. In the 
absence of a thermometer it is usual to heat 



168 THE CHEMISTRY OF 

the oven to a point slightly below the tempera- 
ture necessary to brown cotton, and expose the 
objects no less than one hour. 

"Dry heat fixes many stains, so that they will 
not wash out." This is especially marked with 
albuminous materials coagulable by heat, and 
the method should not be used for the disinfec- 
tion of fabrics and objects soiled with blood, 
sputum, excreta or similar substances." 

The objection to such use of the oven lies in 
the handling of infected articles in the kitchen, 
the worst place in the house to set free these 
dangerous plants. 

steam. "Steam is the most valuable disinfecting agent 

we possess. It is reliable, quick, and may be 
depended upon to penetrate deeply" if the appli- 
cation is prolonged. "It does more than disin- 
fect; it sterilizes. Bacteria are killed instantly, 
spores are killed in a few minutes, and it may 
therefore be used to destroy the infection of any 
one of the communicable diseases. . . ." 

"Steam is very apt to shrink woolens and in- 
jure silk fabrics. It ruins leather, fur, skins of 
all kinds, also rubber shoes, mackintoshes and 
similar articles made of impure rubber." 

Boiling. "Boiling is such a commonplace, every-day 

process that it is often neglected in practical dis- 
infection, despite the fact that it is one of the 
readiest and most effective methods of destroy- 
ing infection of all kinds. An exposure to 
boiling water at ioo° C, continued half an hour, 
will destroy the living principles of all the 



COOKING AND CLEANING. 169 

known infectious diseases, even very resisting 
spores. . . ." 

"Boiling is particularly applicable to the dis- 
infection of bedding, body linen, towels and 
fabrics of many kinds ; to kitchen and tableware ; 
to cuspidors, urinals and a great variety of ob- 
jects. Surfaces, such as floors, walls, beds, fur- 
niture, etc., may be effectively disinfected by 
mechanically cleansing them with boiling water. 
The efficacy of boiling water, especially when 
used under such circumstances, is greatly in- 
creased by the addition of corrosive sublimate, 
carbolic acid, or any one of the soluble germi- 
cidal agents. The addition of lye, borax or a 
strong alkaline soap greatly increases the pene- 
trating power of boiling water, when applied to 
surfaces soiled with organic or oleaginous 
matters." 

"In using boiling water for the disinfection of 
bright steel objects or cutting instruments, the 
addition of one per cent of an alkaline substance 
(bicarbonate of soda) will prevent rusting and 
injury to the cutting edge." 

"In the household, small objects, body and bed 
linen, and other fabrics may be thoroughly disin- 
fected by streaming steam by placing a large pot 
or washboiler on the kitchen fire, and arranging 
broom handles across the top to hold the mate- 
rials to be disinfected. The whole should be 
covered with a sheet or cloth to retain the heat, 
and steamed for an hour or longer, depending 
upon the degree of penetration required and the 
energy with which the water boils," 



170 



THE CHEMISTRY OF 



Fire. 



Solutions. 



Formalin. 



Here, again, excessive precautions must be 
taken in handling such materials in the kitchen. 

Fire is by all means the surest disinfectant. 
Anything which can be burned is reduced to its 
inorganic elements, and these are not food for 
the pathogenic germs. 

Whenever any infectious material is liable to 
be produced, as in all discharges from commu- 
nicable diseases, an effort should be made to 
receive it in or upon combustible materials of 
little value which can be burned immediately. 

Solutions. These must not only be strong 
enough, but in such quantity that the strength 
shall not be diluted by the infectious material 
beyond the effective point. The time of action 
is also an essential factor. If the microbes are 
dry it will take a certain time to wet them before 
the chemical action can take place. Unless the 
infected material can be immersed in the disin- 
fectant solution, it is difficult to keep the two in 
contact long enough to effect safety. Tempera- 
ture, also, is an important factor in successful 
disinfection. It is always well to use warm — 
hot, if possible — solutions and combine their 
action with mechanical removal, or scrubbing. 

Formalin is a solution of formaldehyde. A 
very small amount is antiseptic, even i in 25,000 
or 50,000, while one to four per cent kills in a 
short time. This method kills spores, also. 



COOKING AND CLEANING. 171 

Lime or quicklime, CaO, is an alkaline earth. 
It is very caustic and therefore useful in destroy- 
ing organic matter. 

Calcium hydrate, slaked lime, Ca(OH) 2 , is siakedLime. 
made by adding one part of water to two parts 
of quicklime. 

For a disinfectant, freshly slaked lime should 
be used. When the slaked lime is exposed to 
the air it readily takes up carbon dioxide and is 
converted into calcium carbonate, which has no 
particular disinfecting power. 

Whitewash is slaked lime mixed with water, whitewash. 
It is an excellent disinfectant for surfaces, and is 
a form of milk of lime, which is slaked lime 
with about four times its volume of water. Milk 
of lime must be prepared from freshly slaked 
lime and should be thoroughly stirred to prevent 
the insoluble hydrate from settling. At least 
two hours' contact should be allowed when this 
is used for disinfecting excreta, and it should be 
thoroughly incorporated. Milk of lime as used 
for the disinfection of excreta in the United 
States Army posts is made from one part, by 
weight, of freshly slaked lime to eight parts of 
water. The excreta should stand in this at least 
two hours before disposal. 

Ferrous sulphate, green vitriol, as copperas, Copperas. 
FeS0 4 , so commonly depended upon as a disin- 



172 THE CHEMISTRY OF 

fectant, has been found to be practically useless. 
It is a fairly good deodorant, 
carbolic Add. Carbolic acid, C 6 H 5 OH, phenol, does not co- 

agulate albuminous matter so readily as corro- 
sive sublimate. It cannot be depended upon to 
kill spores, but is fairly good for the vegetative 
stage. In the strengths necessary for disinfec- 
tion it is not destructive to fabrics, colors, metals 
or wood. 

It should be used in a 1-20 solution. If much 
is required it will be cheaper to buy the con- 
centrated, which is a ninety-five per cent solution, 
and reduce it to the desired strength. Four 
ounces of this strength with five pints of boiling 
water will give the required 1-20 solution. The 
strong acid is very corrosive and must not touch 
the skin. ♦ 

Quoting again from Dr. Rosenau's book, we 
find that "in general practice carbolic acid is 
used in from three to five per cent solutions, and 
an exposure of no less than half an hour. Cloth- 
ing and fabrics require deep penetration, and are 
usually left in the solution one hour." 
c-esois. Crcsols are a class of substances obtained from 

coal tar, found as impurities in commercial car- 
bolic acid or phenol. 

Their value is variable. Creolin is a common 
and cheap member of this class. It contains 



COOKING AND CLEANING. 173 

about ten per cent of cresols and a small amount 
of phenol held in solution by soap. It is at least 
equal to and usually superior to the phenol. A 
one per cent solution is effective for ordinary 
purposes. 

Potassium permanganate, KM 4 4 , the cham- p°JJJ s j, u ™ t 
aeleon minerale, as it was called by the early 
chemists, is a powerful oxidizing agent and a 
strong germicide under limited conditions. It is 
readily reduced and rendered inert by organic 
matter. 

Swampy water may be purified by it if enough 
is added to allow the faint pink color to remain 
when the brown precipitate which has enmeshed 
the bacteria is settled or filtered off. 

There is a possible danger of internal irrita- 
tion when this chemical is used continuously in 
potable waters. 

Mercuric chloride, HptCL, corrosive sublimate. Corrosive 

. . , t « •« i i • i Sublimate. 

is a potent germicide. It kills both active and 
spore forms. It is a virulent poison, corrodes 
metals, and unless used with salt it coagulates 
albuminous matter. For disinfection of excreta, 
therefore, salt must be added. It dissolves with 
some difficulty in three parts of boiling water 
or sixteen parts cold water. It should, there- 
fore, be powdered before the water is added, 
care being taken not to inhale the dust. The 



174 THE CHEMISTRY OF 

solution is colorless and odorless, and has been 
mistaken for water when not properly labeled. 
The commercial tablets contain salt and are often 
colored blue. The solution may be slightly col- 
ored with indigo, or any of the aniline dyes, and 
this should be done always as a precautionary 
measure. 

The i-iooo strength is sufficient to kill non- 
spore-bearing species if allowed to act for half 
an hour. For spores the 1-500 solution and an 
hour's exposure is required. 

A gaseous disinfectant is ideal if it can be 
made to penetrate thick fabrics when they are 
slightly moist, so that the gas may be absorbed 
and brought into intimate contact. This is diffi- 
cult to accomplish for the housewife, because 
the gas must be delivered under pressure. 
Formaldehyde. At present, formaldehyde seems to approach 
this ideal most nearly. It is non-poisonous, does 
not injure fabrics, metals or mineral surfaces. 
In disinfecting with formaldehyde, temperature 
plays an important part. The gas is not effective 
under 50 F. and increases in power with the 
higher temperatures. Moisture, also, is neces- 
sary for its effectiveness. A basin of water, kept 
boiling, may be used to furnish the moisture. 
The gas does not penetrate thick masses or fab- 
rics readily, unless it is delivered under pressure, 



COOKING AND CLEANING. 175 

therefore such articles should be spread out as 
thin as possible, and more time should be allowed 
than for ordinary disinfection. 

When the disinfection of a room with a gas 
is completed, the doors and windows should be 
opened as quickly as possible. If a person enters 
the room to do this, he should cover the eyes, 
nose and mouth with a moist cloth to prevent 
the • irritation caused by the gas. Ammonia 
sprinkled about the room will neutralize the gas, 
but forms with it a substance having a very 
persistent odor. 

Soaps have an antiseptic action, and it is Soa P s - 
asserted by many that pure white castile soap 
is germicidal. 

According to Dr. Rosenau: "Medicated soaps 
are for the most part a snare and a delusion so 
far as any increased germicidal action is con- 
cerned ; in fact, the addition of carbolic acid, bi- 
chloride of mercury, and other substances which 
have the property of combining with the soap, 
seems actually to diminish the disinfecting value 
of that substance. As a rule, a very small quan- 
tity of the disinfecting substance is added to the 
soap, and when it is called to mind what an ex- 
ceedingly small quantity of soap is necessary for 
the ordinary washing of the skin, and the further 
dilution of this small amount by the water used, 



176 THE CHEMISTRY OF 

it is easy to understand that medicated soaps, as 
ordinarily applied, cannot have an energetic 
disinfecting action." 

The value of soap is in its superficial cleansing, 
the removal of objectionable matter. 
Deodorants. Another class of substances which are often 

used, and sometimes with danger, are those 
which destroy odors. These are substances 
which combine with the decomposing matter, 
forming new and odorless compounds. Charcoal 
is such a substance. 

This is the office of a true deodorant. The 
name is sometimes applied to other substances 
which produce no chemical or physical changes, 
but simply cover up the odor given ofT by the 
decaying matter by one stronger or more 
agreeable. 

Deodorants simply destroy smells ; disinfect- 
ants and germicides destroy germs. Most disin- 
fectants are at the same time deodorants. 

The question is constantly asked, "What disin- 
fectants can I use that are common and cheap?" 

The last published report of the American 
Public Health Association speaks authoritatively 
upon this question, and from this the following 
quotation may be taken as a summary of the 
present status of the subject: 
ummonule/™ "The weight of opinion seems to be that alco- 



COOKING AND CLEANING. 177 

hoi from 40-60% is quite a strong germicide, 
but that lower and higher percentages are much 
weaker in their action. Two observers class it 
about midway between sublimate and carbolic 
acid in strength. 

"Whether it acts as a direct poison or indi- 
rectly through the water present is not yet estab- 
lished, but the weight of opinion seems to be that 
it acts directly." 

The vapor from boiling alcohol solutions 
is more effective as a disinfectant than the 
solutions. 

"There are a few common disinfectants the 
efficiency of which has been firmly established, 
namely, boiling water, hot soda solution (about 
10% solution of sal-soda in water), milk of lime 
(pieces of lime slacked to a milk), corrosive sub- 
limate and formaldehyde. I would add some of 
the cresol preparations except that they are pat- 
ented and hence not cheap enough for common 
use in the United States. I leave out carbolic 
acid because of its poisonous properties, and 
chloride of lime because of its uncertain compo- 
sition. Nothing better or more effective is 
needed to disinfect feces and such matters than 
milk of lime ; nothing to disinfect clothes than 
steam, hot water or hot soda solution ; for quick 
sterilization of the hands a 1-1000 sublimate solu- 
tion is the best ; and as a room disinfectant, 
formaldehyde properly used still holds the first 
place. . . ." 

Some insects are known to carry infectious Insects - 



178 THE CHEMISTRY OF 

matter, and it is easy to understand how any 
animal may convey such material from one place 
to another and possibly to man. They certainly 
do carry on their bodies minute infectious parti- 
cles gathered from moist substances, as excreta, 
pus, sputum, over which they have crawled. 
They carry also the agents of decomposition 
from decaying food, depositing them upon other 
food and thus starting decomposition in it. 

In some cases the infectious germ is intro- 
duced into human beings from the body of the 
insect as it stings or bites. This is the case with 
the flea and the mosquito, which carry malarial 
and yellow fever germs. 

The flies, fleas, ants, etc., deposit the infectious 
material on the skin with their excrement, and in 
other ways. The virulent infection is rubbed 
into the little wounds or scratched into the skin 
as a result of the irritation caused by the bites, 
thereby setting up the disease. 

Therefore all insects may be looked upon with 
suspicion, while mosquitoes, flies, roaches, bed- 
bugs and fleas should receive no quarter in the 
clean and healthful house, 
insecticides. Most germicides are insecticides. Yet formal- 

dehyde is a notable exception. It has slight 
effect upon insect life. 

Sulphur dioxide. This gas holds first place 



COOKING AND CLEANING. 17d 

for killing insects and vermin. As an insecticide 
it can be used dry, while as a germicide, as has 
been said, moisture is necessary. 

Bisulphide of carbon, CS 2 , and hydrocyanic 
acid gas, HCN, are both powerful insecticides. 
They are also deadly poisons to all animal life. 
They should therefore never be used except by 
experts. The United States Government has 
published some valuable bulletins upon the use 
of these substances. 

Kerosene kills bedbugs and their eggs. Ap- 
plied to the surface of water at the rate of an 
ounce to fifteen square feet of surface it destroys 
mosquitoes and their larvae. It is therefore use- 
ful in covering all moist matter in which they 
may breed. 

"Insect powder" or " Persian or Dalmatian in- 
sect powder," is usually the powdered flowers of 
two species of chrysanthemum, C. roseum and 
C. carneum. They are also sold under the names 
of pyrethrum and buhack. The powder acts 
mostly by filling the breathing holes, causing 
suffocation. It will kill, but too often only stu- 
pefies the insects, which should then be gathered 
and burned. Water bugs and fleas are driven 
from their lairs to be caught while stupefied. 

The powder may be burned, and in this form 
is quite effectual for mosquitoes. 



180 THE CHEMISTRY OF 

The poisonous fly papers kill the insects, but 
they fall everywhere about the house, and the 
presence of these arsenical compounds is dan- 
gerous wherever there are children. 

The sticky fly papers do not kill but hold the 
insects, and they die from exhaustion, 



BOOKS OF REFERENCE. 



Approved Methods for Home Laundering. M. B. Vail. 

Art and Practice of Laundry Work. M. C. Rankin. 

Bacteria, Yeasts and Molds in the Home. H. W. Conn. 

Care of a House. T. M. Clark. 

Chemistry of the Household. M. E. Dodd. 

Chemistry of Plant and Animal Life. Harry Snyder. 

Clean Milk. S. D. Belcher. 

Disinfection and Disinfectants. M. J. Rosenau. 

Domestic Economy in Theory and Practice. Bidder and 

Baddely. 
Drinking Water and Ice Supplies. T. M. Prudden. 
Dust and Its Dangers. T. M. Prudden. 
Elementary Laundry Work. Calder and Mann. 
Expert Cleaner. H. J. Seaman. 
Garment Dyeing and Cleaning. G. H. Hurst. 
Handbook of Domestic Science and Household Arts. 

L. L. W. Wilson. 
Handbook on Sanitation. G. M. Price. 
Home Furnishing. A. M. Kellogg. 
Home Sanitation. Richards and Talbot. 
House and Home. M. E. Carter. 
House that Jill Built. E. C. Gardner. 
Household Bacteriology. S. M. Elliott. 
Household Economics. Helen Campbell. 
Household Hygiene. S. M. Elliott. 
How to Drain a House. G. E. Waring, Jr. 
Hygiene and Public Health. L. C. Parkes, 



182 BOOKS OF REFERENCE. 

Laboratory Notes in Household Chemistry. Vulte and 

Goodell. 
Laundry Manual. Balderston and Limerick. 
Laundry Work. J. L. Sheppard. 
Outlines of Rural Hygiene. H. B. Bashore. 
Principles of Sanitary Science and Public Health. W. T. 

Sedgwick. 
Sanitary and Applied Chemistry. E. H. S. Bailey. 
Sanitation of a Country House. H. B. Bashore. 
School Sanitation and Decoration. Burrage and Bailey. 
Story of the Bacteria. T. M. Prudden. 
Story of Germ Life. H. W. Conn. 
Story of the Living Machine. H. W. Conn. 
Text-Book of Physiological Chemistry. Hammersten. 
Text-Book of Physiology. William Howell. 



INDEX. 



Absorbents of grease, 100, 101, 163 
Acids, 41, 151 

Acetic, 38, 152 

Butyric, 35 

Carbolic, 172 

Citric, 152 

for iron stains, 132 

Hydrochloric or Muriatic, 17, 41, 
132, 153 

Lactic, 152 

Oxalic, 116, 153 

Stearic, 43 

Tannic, 50 

Tartaric, 153 
Air, as food, 67 

not the agent of change, 73 

pollution of, 84 

pure, 83 

a substance, 85 
Albumin, 49 
Albuminoids, 50 
Alcohol, 30, 36, 159 
Alcohol, as solvent, 102, 110, 157 
Alkalies, caustic, 89, 111, 146 

volatile, 89 
Alkali metals, 88 
Alum, 163 
Aluminum, 117 
Ammonia, 89, 150 

uses of, 73, 93, 102, 125, 139, 150 
Ammonium, 88, 89 
Animal body, a living machine, 47 

repair of, 48 
Antisepsis, 165 
Art of cooking, 56, 62 
Atoms, 14 
Atomic weight, 14, 16 

of hydrogen, 14 

Bacteria, 36, 39, 74, 76, 77, 81 

action of in disease, 80 

as flavor producers, 62 

food of, 81 

spores of, 75 
Bacteriology of bread-making, 36 
Baking powder, 22, 23 



Beans, 52, 64 

Beer, 29 

Benzine, 98, 102, 157 

Biscuits, 39 

Bleachers, 154 

Bleaching, 134, 135 

Bleaching powder, 135, 156 

Blinds, 82 

Blood stains, 106, 129 

Blotting paper for ink, 108 

Bluing, 133, 134, 161 

Boiling, 168 

Books for reference, 181 

Borax, 125, 128, 137, 139, 149 

Brass, 116 

Bread-making, chemical reactions in, 

29, 30, 36 
Bread, as food, 33 

crust, 39 

fermented, 36 

flavor in, 39 4 

homemade, 37 

ideal, 34 

leavened, 35 

object of baking, 38 

reason for kneading, 37 

stale, 39 

temperature of baking, 37, 38, 39, 54 
of fermentation, 37 
Butter, 43 
Butyric acid, 35 

Caesium, 88 

Calcium hypochlorite, 128, 156 
Calories, 47 
Calorimeter, 19 
Cane sugar, 28,29 
Carbohydrates, 26, 44, 63 
Carbolic acid, 172 
Carbon bisulphide of, 179 
Carbon dioxide (carbonic acid gas), 
17, 18, 19,25,30,36,37 
method of obtaining, 40 
Carbon tetrachloride, 157 
Casein, 52 
Caustic alkalies, 89, 147, 148 



184 



INDEX. 



Cayenne pepper, 59 
Cellulose, 27 

Cheese cloth for cleaning, 93 
Chemical arithmetic, 17 
Chemical change, 7 

produces heat, 25 
Chemical elements, 12, 16 
Chemical equations, 17 
Chemical experiments in the home, 145 
Chemical laws, 13, 14, 15 
Chemical reactions, 17, 25 

in bread and beer making, 36 
Chemical symbols, 16 
Chemicals for household use, 145 
Chloride of lime, 126, 127, 128, 129, 

156, 177 
Chloroform, 102,157,158 
Cleaning of brass, 116 

fabrics, 97, 98 

glass, 96 

paint, 93 

powders, 113 

problems of, 90 

processes of, 88, 90 

silver, 111, 116' 

wood, 90, 91,92, 93 
Cleanness, ideal and sanitary, 142 

personal, 143 

philosophy of, 82, 85 

public, 144 

of schoolhouses, 144 
Cocoa and coffee stains, 127, 128 
Collagen, 50 

Colors, setting of, 140, 146 
Combining weights, 14 
Combustion of food, 25, 26 

products of, 84 
Compounds, 13 
Condiments, 56, 58, 59 
Consumption, 83 
Conversion of starch, 28, 30 
Cooking, American, 58 

art of, 56, 57, 62 

chemistry of, 58 

discretion in, 62 

economy in, 60 

effect of, 54 

fats, 46 

nitrogenous food, 50, 53 

object of, 53 

starch, 32 

vegetables, 60 
Copper, 115, 116 
Copperas, 171 
Corrosive sublimate, 173 
Cottonseed oil. 43 



Cream of tartar, 23, 41, 42 
Creolin, 192 
Cresols, 192 

Decomposition, 64 

Definite proportions, law of, 14 

Deodorants, 176 

Development of flavor, 56 

Dextrose, 29 

Diastase, 29 

Diet, 63, 65 

Diet, fat in, 45 

Dietaries, 68, 69 

Digestion, 28, 61,63, 66 

of fats, 44 

is solution, 28 
Dirt, definition of, 78 

prevention of, 98 
Disease, cause of, 80 

prevention of, 79 
Dish cloths and towels, 140 
Disinfectants, 166, 176 
Disinfection, 166 
Dry heat, 167 
Dust, 71,72,73,75,87,88 

in air, 72, 76 

composed of, 77 

on fabrics, 97 ,98 

germs, 80 

meteoric, 73 

spots, 103 

on wood, 92 

Economy in cooking, 60 

of mixed diet, 65 
Effect of condiments, 58 

of cooking, 54 
Eggs, 51 

Elements, chemical, 12, 16 
Emery, 162 
Energy, mechanical unit of, 47 

sources of, 44 
Ether, 102, 157, 158 
Expansion of gases, 9 

of water, 40 

Fabrics, 97, 98 
Fat, digestion of, 44 

in diet, 44 

effect of high temperature on, 46 
Fats, 24, 43, 45, 55, 88 
Fermentation, 35, 39 
Finish of woods, 90 
Fire, 170 

Flavor, 46, 56, 57, 58, 60 
Flour, use of, in bread, 39 



INDEX. 



185 



Food, office of, 24,69 
water and air as, 68 
Formaldehyde, 174 
Formalin, 170 
French chalk, 163 
Frictional materials, 162 
Fruit stains, 126, 127 
Fuel in body, 47 
Fuller's earth, 163 
Fungi, 74 

Gases, 8 

Gasoline, 157 

Germs, 74, 80, 81 

Glass, 96 

Glucose, 29 

Gluten, 52 

Grass stains, 129 

Grease, 87, 88, 100, 101, 102, 104, 135 

solvents for, 91, 157 

on wood , 103 
Growth, nitrogenous food required 

for, 48 
Gums, 24 

Hard water, 119, 120 
Heat, dry, 167 

produced by chemical change, 24 

source of in animals, 25 
Hydrochloric acid, 41, 153 
Hydrogen, 14, 27, 44 
Hydrogen peroxide, 155 
Hyposulphite, 157 

Ideal bread, 34 
Indigo, 133 

Inflammable substances, 98 
Ink indelible, 109 

stains, 107, 108, 131 
Inoculation, 82 
Insect powder, 179 
Insecticides, 178 

Iron rust, removal of, 117, 131, 132, 
146 

Javelle water, 126, 127, 128, 129, 130, 

157 
Jewelry, 115 

Kerosene , 91 , 92, 96, 111 , 116, 117, 131 , 

141, 157, 179 
Kitchen utensils, 117 

Lard, 43 
Laundry, 118-142 



Law of definite proportions, 14 

multiple proportions, 15 
Leather, 94 
Leaven, 35 
Legumin, 52 
Lentils, 65 
Levulose,29 
Lime, slaked, 171 
Lithium, 88, 89 
Litmus paper, 163 

Marble, 95, 109 
Matter, changes in, 5 

definition of, 5 

forms of, 8 
Medicine stains, 127 
Mercuric chloride, 173 
Metals, 95, 111,116 
Mildew, 130 
Milk stains, 129 
Mixed diet, 65 
Molds, 74, 77, 79 
Molecular weight, 11 
Molecules, 14 
Mucous stains, 129 
Multiple proportions, law of, 15 
Muriatic acid, 153 

Naphtha, 157 
Nature's scavengers, 78 
Nickel, 117 
Nitrogen, 48 

Nitrogenous food, 47, 49, 68 
cooking of, 50, 55 

Oils, 43, 45, 88,92,158 
Oil finish, 91 
Oil stains, 130 
Olive oil, 44, 45 
Oxalic acid, 147 
Ox-gall, 103, 151 
Oxygen, 15, 26, 43 
Oysters, 51 

Paint, 93, 104 
Paper, 94 
Pastry, 54 

Pathogenic germs, 81 
Pearlash,149 
Pepsin, 64 
Peptones, 64 
Physical change, 7 
Pipe clay, 163 
Pitch, 105 

Plated silverware, 112 
cyanide, 113 



186 



INDEX. 



Plumbing, care of, 141 

Porcelain, 96, 110 

Potash, 103, 122, 123, 147 

Potassium, 88 

Potassium hydroxide, 147 

Potassium permanganate, 173 

Preparation for food, of starch, sugar 
and fat, 24 

Prevention, 80, 98 

Products of decomposition, 64 

Proportion of nitrogenous food re- 
quired, 68 

Pumice, 95, 162 

Rations, 69 

Removal of dust, spots and stains, 87 

Restoring color, 97 

Rouge, 162 

Rotten-stone, 162 

Rubidium, 88 

Rust of iron, 117 

Saliva, 63 
Sal-soda, 148 
Salt, 17,41,42 
Saturation, 9 

Schoolhouse sanitation, 143 
Seasonable diet, 65 
Serving, 62 

Shellac, dissolved by alcohol, 111 
Silicon , 162 

Silver, cleaning of, 111, 113, 114, 115 
Silver nitrate, 157 
Silver polish, 113, 114 
Silverware, 112, 115 
Soap, 89, 120, 122, 124, 137, 139, 151, 
175 

bark, 121 

berry tree, 121 
Soda, 42, 122, 124,148,149 
Soda ash, 17, 123, 124, 148 
Sodium, 87 

Sodium carbonate, 148 
Sodium chloride, 17, 164 
Sodium hydroxide, 148 
Sodium thiosulphite, 157 
Soft water, 119, 120 
Solution, 9, 28, 50 
Solutions, disinfecting, 170 
Solvents, 10, 78, 91, 101, 102, 106, 157 



Source of energy, 44 

Spores, 75 

Spots, 100, 118 

Stains, 100, 106, 118, 126, 127, 128 

Starch, 24, 27, 28, 29, 30, 31, 160 

cooking of, 32, 55, 61, 160 
Steam, 168 
Stearic acid, 43 
Stiffening agents, 159, 160 
Stimulants, 60 
Stoves, care of, 117 
Suet, 43 
Sugar, 24, 27, 29 

cane, 28 

fruit, 28 

of lead, 163 

milk, 27, 28 
Sulphur dioxide, 156, 178 
Sunlight, 82, 83, 84, 85, 154, 166 
Swelling, 10 
Symbols, 16 
Syrups, 10 

Tables, 16, 23 

Tannin, 128 

Tarnish, 100, 101 

Tea stains, 127, 128 

Temperature, 26, 46, 49, 52, 53 

Tripoli, 162 

Turpentine, 91, 102, 103, 126, 158 

Ultramarine, 133, 134, 162 
Utensils, kitchen, 117 

Varnish, 91, 105 
Vegetables, 60 

Wall paper, 94 

Washing soda, 124, 125, 148 

Water, 118, 119, 120 

as food, 67 

hard and soft, 119, 120 
Wax, 91, 105 
Whiting, 114, 162 
Wine stains, 121 
Whitewash, 171 
Wood finish, 90,91,92 
Woolens, washing of, 139 

Yeast, 33, 35, 36, 37, 38, 74, 78 




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